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Dyson ZA, Ashton PM, Khanam F, Chunga Chirambo A, Shakya M, Meiring JE, Tonks S, Karkey A, Msefula C, Clemens JD, Dunstan SJ, Baker S, Dougan G, Pitzer VE, Basnyat B, Qadri F, Heyderman RS, Gordon MA, Pollard AJ, Holt KE. Pathogen diversity and antimicrobial resistance transmission of Salmonella enterica serovars Typhi and Paratyphi A in Bangladesh, Nepal, and Malawi: a genomic epidemiological study. THE LANCET. MICROBE 2024; 5:100841. [PMID: 38996496 PMCID: PMC11300424 DOI: 10.1016/s2666-5247(24)00047-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 07/14/2024]
Abstract
BACKGROUND Enteric fever is a serious public health concern. The causative agents, Salmonella enterica serovars Typhi and Paratyphi A, frequently have antimicrobial resistance (AMR), leading to limited treatment options and poorer clinical outcomes. We investigated the genomic epidemiology, resistance mechanisms, and transmission dynamics of these pathogens at three urban sites in Africa and Asia. METHODS S Typhi and S Paratyphi A bacteria isolated from blood cultures of febrile children and adults at study sites in Dhaka (Bangladesh), Kathmandu (Nepal), and Blantyre (Malawi) during STRATAA surveillance were sequenced. Isolates were charactered in terms of their serotypes, genotypes (according to GenoTyphi and Paratype), molecular determinants of AMR, and population structure. We used phylogenomic analyses incorporating globally representative genomic data from previously published surveillance studies and ancestral state reconstruction to differentiate locally circulating from imported pathogen AMR variants. Clusters of sequences without any single-nucleotide variants in their core genome were identified and used to explore spatiotemporal patterns and transmission dynamics. FINDINGS We sequenced 731 genomes from isolates obtained during surveillance across the three sites between Oct 1, 2016, and Aug 31, 2019 (24 months in Dhaka and Kathmandu and 34 months in Blantyre). S Paratyphi A was present in Dhaka and Kathmandu but not Blantyre. S Typhi genotype 4.3.1 (H58) was common in all sites, but with different dominant variants (4.3.1.1.EA1 in Blantyre, 4.3.1.1 in Dhaka, and 4.3.1.2 in Kathmandu). Multidrug resistance (ie, resistance to chloramphenicol, co-trimoxazole, and ampicillin) was common in Blantyre (138 [98%] of 141 cases) and Dhaka (143 [32%] of 452), but absent from Kathmandu. Quinolone-resistance mutations were common in Dhaka (451 [>99%] of 452) and Kathmandu (123 [89%] of 138), but not in Blantyre (three [2%] of 141). Azithromycin-resistance mutations in acrB were rare, appearing only in Dhaka (five [1%] of 452). Phylogenetic analyses showed that most cases derived from pre-existing, locally established pathogen variants; 702 (98%) of 713 drug-resistant infections resulted from local circulation of AMR variants, not imported variants or recent de novo emergence; and pathogen variants circulated across age groups. 479 (66%) of 731 cases clustered with others that were indistinguishable by point mutations; individual clusters included multiple age groups and persisted for up to 2·3 years, and AMR determinants were invariant within clusters. INTERPRETATION Enteric fever was associated with locally established pathogen variants that circulate across age groups. AMR infections resulted from local transmission of resistant strains. These results form a baseline against which to monitor the impacts of control measures. FUNDING Wellcome Trust, Bill & Melinda Gates Foundation, EU Horizon 2020, and UK National Institute for Health and Care Research.
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Affiliation(s)
- Zoe A Dyson
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.
| | - Philip M Ashton
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Angeziwa Chunga Chirambo
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - James E Meiring
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK; Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Centre for Tropical Medicine and Global Health, Medical Sciences Division, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - John D Clemens
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; International Vaccine Institute, Seoul, South Korea
| | - Sarah J Dunstan
- Department of Infectious Diseases, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Stephen Baker
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, University of Cambridge, Cambridge, UK
| | - Gordon Dougan
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, University of Cambridge, Cambridge, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases and the Public Health Modeling Unit, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Centre for Tropical Medicine and Global Health, Medical Sciences Division, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Robert S Heyderman
- NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK; Kamuzu University of Health Sciences, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Kathryn E Holt
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia
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Khaki JJ, Meiring JE, Thindwa D, Henrion MYR, Jere TM, Msuku H, Heyderman RS, Gordon MA, Giorgi E. Modelling Salmonella Typhi in high-density urban Blantyre neighbourhood, Malawi, using point pattern methods. Sci Rep 2024; 14:17164. [PMID: 39060281 PMCID: PMC11282181 DOI: 10.1038/s41598-024-66436-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 07/01/2024] [Indexed: 07/28/2024] Open
Abstract
Salmonella Typhi is a human-restricted pathogen that is transmitted by the faecal-oral route and causative organism of typhoid fever. Using health facility data from 2016 to 2020, this study focuses on modelling the spatial variation in typhoid risk in Ndirande township in Blantyre. To pursue this objective, we developed a marked inhomogeneous Poisson process model that allows us to incorporate both individual-level and environmental risk factors. The results from our analysis indicate that typhoid cases are spatially clustered, with the incidence decreasing by 54% for a unit increase in the water, sanitation, and hygiene (WASH) score. Typhoid intensity was also higher in children aged below 18 years than in adults. However, our results did not show evidence of a strong temporal variation in typhoid incidence. We also discuss the inferential benefits of using point pattern models to characterise the spatial variation in typhoid risk and outline possible extensions of the proposed modelling framework.
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Affiliation(s)
- Jessie J Khaki
- The Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster University, Lancaster, UK.
- Malawi Liverpool-Wellcome (MLW) Trust Programme, Blantyre, Malawi.
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi.
| | - James E Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Deus Thindwa
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, USA
| | - Marc Y R Henrion
- Malawi Liverpool-Wellcome (MLW) Trust Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tikhala M Jere
- Malawi Liverpool-Wellcome (MLW) Trust Programme, Blantyre, Malawi
| | - Harrison Msuku
- Malawi Liverpool-Wellcome (MLW) Trust Programme, Blantyre, Malawi
| | - Robert S Heyderman
- Division of Immunity and Infection, Veterinary and Ecological Sciences, University College London, London, UK
| | - Melita A Gordon
- Malawi Liverpool-Wellcome (MLW) Trust Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Emanuele Giorgi
- The Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster University, Lancaster, UK
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3
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Ahmmed F, Khanam F, Islam MT, Kim DR, Kang S, Firoj MG, Aziz AB, Hoque M, Liu X, Jeon HJ, Kanungo S, Chowdhury F, Khan AI, Zaman K, Marks F, Kim JH, Qadri F, Clemens JD, Tadesse BT, Im J. Spatial and temporal clustering of typhoid fever in an urban slum of Dhaka City: Implications for targeted typhoid vaccination. PLoS Negl Trop Dis 2024; 18:e0012273. [PMID: 38913735 PMCID: PMC11226105 DOI: 10.1371/journal.pntd.0012273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 07/05/2024] [Accepted: 06/06/2024] [Indexed: 06/26/2024] Open
Abstract
BACKGROUND Salmonella enterica serotype Typhi (Salmonella Typhi) causes severe and occasionally life-threatening disease, transmitted through contaminated food and water. Humans are the only reservoir, inadequate water, sanitation, and hygiene infrastructure increases risk of typhoid. High-quality data to assess spatial and temporal relationships in disease dynamics are scarce. METHODS We analyzed data from a prospective cohort conducted in an urban slum area of Dhaka City, Bangladesh. Passive surveillance at study centers identified typhoid cases by microbiological culture. Each incident case (index case) was matched to two randomly selected index controls, and we measured typhoid incidence in the population residing in a geographically defined region surrounding each case and control. Spatial clustering was evaluated by comparing the typhoid incidence in residents of geometric rings of increasing radii surrounding the index cases and controls over 28 days. Temporal clustering was evaluated by separately measuring incidence in the first and second 14-day periods following selection. Incidence rate ratios (IRRs) were calculated using Poisson regression models. RESULTS We evaluated 141 typhoid index cases. The overall typhoid incidence was 0.44 per 100,000 person-days (PDs) (95% CI: 0.40, 0.49). In the 28 days following selection, the highest typhoid incidence (1.2 per 100,000 PDs [95% CI: 0.8, 1.6]) was in the innermost cluster surrounding index cases. The IRR in this innermost cluster was 4.9 (95% CI: 2.4, 10.3) relative to the innermost control clusters. Neither typhoid incidence rates nor relative IRR between index case and control populations showed substantive differences in the first and second 14-day periods after selection. CONCLUSION In the absence of routine immunization programs, geographic clustering of typhoid cases suggests a higher intensity of typhoid risk in the population immediately surrounding identified cases. Further studies are needed to understand spatial and temporal trends and to evaluate the effectiveness of targeted vaccination in disrupting typhoid transmission.
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Affiliation(s)
- Faisal Ahmmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Md Taufiqul Islam
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Deok Ryun Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Sophie Kang
- International Vaccine Institute, Seoul, Republic of Korea
| | - Md Golam Firoj
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Masuma Hoque
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Xinxue Liu
- Oxford Vaccine Group, Department of Pediatrics, University of Oxford, Oxford, United Kingdom
| | - Hyon Jin Jeon
- International Vaccine Institute, Seoul, Republic of Korea
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Suman Kanungo
- ICMR- National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
| | - Fahima Chowdhury
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Ashraful Islam Khan
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Khalequ Zaman
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Florian Marks
- International Vaccine Institute, Seoul, Republic of Korea
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Madagascar Institute for Vaccine Research, University of Antananarivo, Antananarivo, Madagascar
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
| | - Jerome H. Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - John D. Clemens
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
- International Vaccine Institute, Seoul, Republic of Korea
- UCLA Fielding School of Public Health, Los Angeles, California, United States of America
- Vaccine Innovation Center, Korea University School of Medicine, Seoul, Republic of Korea
| | | | - Justin Im
- RIGHT Foundation, Seoul, Republic of Korea
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Webster E, Palanco Lopez P, Kirchhelle C. Shifting targets: typhoid's transformation from an environmental to a vaccine-preventable disease, 1940-2019. THE LANCET. INFECTIOUS DISEASES 2024; 24:e232-e244. [PMID: 37995738 DOI: 10.1016/s1473-3099(23)00500-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 11/25/2023]
Abstract
160 years after the discovery of its waterborne transmission and 120 years after the development of the first-generation of vaccines, typhoid fever remains a major health threat globally. In this Historical Review, we use WHO's Institutional Repository for Information Sharing to examine changes in typhoid control policy from January, 1940, to December, 2019. We used a mixed-methods approach in the analysis of infection control priorities, combining semi-inductive thematic coding with historical analysis to show major thematic shifts in typhoid control policy, away from water, sanitation, and hygiene (WASH)-based control towards vaccine-based interventions concurrent with declining attention to the disease. Documentary analysis shows that, although international planners never officially disavowed WASH and low-income countries persistently lobbied for WASH, vaccines emerged as a permanent stopgap while meaningful support of sustained WASH strengthening lost momentum-with serious, long-term ramifications for typhoid control.
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Affiliation(s)
- Emily Webster
- Department of Philosophy, Durham University, Durham, UK; Department of Philosophy, University of Johannesburg, Johannesburg, South Africa
| | | | - Claas Kirchhelle
- School of History, University College Dublin, Dublin, Ireland; Oxford Vaccine Group, University of Oxford, Oxford, UK.
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5
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Feutz E, Biswas PK, Ndeketa L, Ogwel B, Onwuchekwa U, Sarwar G, Sultana S, Peñataro Yori P, Acebedo A, Ahmed N, Ahmed I, Atlas HE, Awuor AO, Bhuiyan MAI, Conteh B, Diawara O, Elwood S, Fane M, Hossen MI, Ireen M, Jallow AF, Karim M, Kosek MN, Kotloff KL, Lefu C, Liu J, Maguire R, Qamar FN, Ndalama M, Ochieng JB, Okonji C, Paredes LFZ, Pavlinac PB, Perez K, Qureshi S, Schiaffino F, Traore M, Tickell KD, Wachepa R, Witte D, Cornick J, Jahangir Hossain M, Khanam F, Olortegui MP, Omore R, Sow SO, Yousafzai MT, Galagan SR. Data Management in Multicountry Consortium Studies: The Enterics For Global Health (EFGH) Shigella Surveillance Study Example. Open Forum Infect Dis 2024; 11:S48-S57. [PMID: 38532952 PMCID: PMC10962719 DOI: 10.1093/ofid/ofad573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
Background Rigorous data management systems and planning are essential to successful research projects, especially for large, multicountry consortium studies involving partnerships across multiple institutions. Here we describe the development and implementation of data management systems and procedures for the Enterics For Global Health (EFGH) Shigella surveillance study-a 7-country diarrhea surveillance study that will conduct facility-based surveillance concurrent with population-based enumeration and a health care utilization survey to estimate the incidence of Shigella--associated diarrhea in children 6 to 35 months old. Methods The goals of EFGH data management are to utilize the knowledge and experience of consortium members to collect high-quality data and ensure equity in access and decision-making. During the planning phase before study initiation, a working group of representatives from each EFGH country site, the coordination team, and other partners met regularly to develop the data management systems for the study. Results This resulted in the Data Management Plan, which included selecting REDCap and SurveyCTO as the primary database systems. Consequently, we laid out procedures for data processing and storage, study monitoring and reporting, data quality control and assurance activities, and data access. The data management system and associated real-time visualizations allow for rapid data cleaning activities and progress monitoring and will enable quicker time to analysis. Conclusions Experiences from this study will contribute toward enriching the sparse landscape of data management methods publications and serve as a case study for future studies seeking to collect and manage data consistently and rigorously while maintaining equitable access to and control of data.
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Affiliation(s)
- Erika Feutz
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Prasanta K Biswas
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Latif Ndeketa
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, UK
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Billy Ogwel
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Uma Onwuchekwa
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Golam Sarwar
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Shazia Sultana
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Pablo Peñataro Yori
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Alyssa Acebedo
- American Association for Cancer Research, Philadelphia, Pennsylvania, USA
| | - Naveed Ahmed
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Imran Ahmed
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Hannah E Atlas
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Alex O Awuor
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | | | - Bakary Conteh
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Oualy Diawara
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Sarah Elwood
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Moussa Fane
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Md Ismail Hossen
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mahzabeen Ireen
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Abdoulie F Jallow
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mehrab Karim
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Margaret N Kosek
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Karen L Kotloff
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Clement Lefu
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Jie Liu
- School of Public Health, Qingdao University, Qingdao, China
| | - Rebecca Maguire
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | | | - John Benjamin Ochieng
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Caleb Okonji
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | | | - Patricia B Pavlinac
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Karin Perez
- Asociación Benéfica Prisma, Iquitos, Loreto, Peru
| | - Sonia Qureshi
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Francesca Schiaffino
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
- Faculty of Veterinary Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Moussa Traore
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Kirkby D Tickell
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | | | - Desiree Witte
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Jennifer Cornick
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - M Jahangir Hossain
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Richard Omore
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Samba O Sow
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | | | - Sean R Galagan
- Department of Global Health, University of Washington, Seattle, Washington, USA
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6
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Mategula D, Ndalama M, Lefu C, Chinkhumba J, Ndeketa L, Munthali V, Chitala C, Malemia T, Million G, Mbutuka I, Mhone R, Makwenda E, James M, Bwanali C, Kazembe G, Manundo A, Chauluka E, Chitalo S, Alumando E, Longwe D, Matandika M, Jonasi P, Thindwa A, Phiri D, Wachepa R, Kawonga F, Maiden V, Charles M, Kapindula I, Witte D, Turner AM, Bronowski C, Baker K, Bar-Zeev N, Gordon MA, Dube Q, Cunliffe NA, Jere KC, Cornick J. The Enterics for Global Health (EFGH) Shigella Surveillance Study in Malawi. Open Forum Infect Dis 2024; 11:S101-S106. [PMID: 38532955 PMCID: PMC10962717 DOI: 10.1093/ofid/ofae050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
Background Malawi is among 7 countries participating in the Enterics for Global Health (EFGH) Shigella surveillance study, which aims to determine the incidence of medically attended diarrhea attributed to Shigella, a leading bacterial cause of diarrhea in children in low-resource settings. Methods We describe the EFGH study site in the densely populated informal settlement of Ndirande Township, Blantyre, Malawi. We explore the site's geographical location, demographic characteristics, and the healthcare-seeking behavior of its population, particularly for childhood diarrhea. We also describe the management of childhood diarrhea at the health facility, and the associated challenges to attaining optimum adherence to local and national guidelines at the site. Conclusions Our overarching aim is to improve global health through understanding and mitigating the impact of diarrhea attributed to Shigella.
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Affiliation(s)
- Donnie Mategula
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Clinical Sciences Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Environmental and Community Health, School of Global Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | | | - Clement Lefu
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Jobiba Chinkhumba
- Department of Environmental and Community Health, School of Global Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Latif Ndeketa
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Department of Environmental and Community Health, School of Global Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | | | | | | | | | | | - Ranken Mhone
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | | | - Mussa James
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | | | - Gift Kazembe
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Abell Manundo
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | | | | | | | | | | | - Paul Jonasi
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Agra Thindwa
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Deborah Phiri
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | | | | | - Victor Maiden
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Mary Charles
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Ida Kapindula
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Desiree Witte
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Ann M Turner
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Christina Bronowski
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Kate Baker
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | | | - Melita A Gordon
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Queen Dube
- Department of Medical Laboratory Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre, Malawi
- Ministry of Health, Government of Malawi, Lilongwe, Malawi
| | - Nigel A Cunliffe
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Khuzwayo C Jere
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Medical Laboratory Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Jennifer Cornick
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
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7
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Ashton PM, Chunga Chirambo A, Meiring JE, Patel PD, Mbewe M, Silungwe N, Chizani K, Banda H, Heyderman RS, Dyson ZA, MacPherson P, Henrion MYR, Holt KE, Gordon MA. Evaluating the relationship between ciprofloxacin prescription and non-susceptibility in Salmonella Typhi in Blantyre, Malawi: an observational study. THE LANCET. MICROBE 2024; 5:e226-e234. [PMID: 38387472 PMCID: PMC10914669 DOI: 10.1016/s2666-5247(23)00327-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 02/24/2024]
Abstract
BACKGROUND Ciprofloxacin is the first-line drug for treating typhoid fever in many countries in Africa with a high disease burden, but the emergence of non-susceptibility poses a challenge to public health programmes. Through enhanced surveillance as part of vaccine evaluation, we investigated the occurrence and potential determinants of ciprofloxacin non-susceptibility in Blantyre, Malawi. METHODS We conducted systematic surveillance of typhoid fever cases and antibiotic prescription in two health centres in Blantyre, Malawi, between Oct 1, 2016, and Oct 31, 2019, as part of the STRATAA and TyVAC studies. In addition, blood cultures were taken from eligible patients presenting at Queen Elizabeth Central Hospital, Blantyre, as part of routine diagnosis. Inclusion criteria were measured or reported fever, or clinical suspicion of sepsis. Microbiologically, we identified Salmonella enterica serotype Typhi (S Typhi) isolates with a ciprofloxacin non-susceptible phenotype from blood cultures, and used whole-genome sequencing to identify drug-resistance mutations and phylogenetic relationships. We constructed generalised linear regression models to investigate associations between the number of ciprofloxacin prescriptions given per month to study participants and the proportion of S Typhi isolates with quinolone resistance-determining region (QRDR) mutations in the following month. FINDINGS From 46 989 blood cultures from Queen Elizabeth Central Hospital, 502 S Typhi isolates were obtained, 30 (6%) of which had either decreased ciprofloxacin susceptibility, or ciprofloxacin resistance. From 11 295 blood cultures from STRATAA and TyVAC studies, 241 microbiologically confirmed cases of typhoid fever were identified, and 198 isolates from 195 participants sequenced (mean age 12·8 years [SD 10·2], 53% female, 47% male). Between Oct 1, 2016, and Aug 31, 2019, of 177 typhoid fever cases confirmed by whole-genome sequencing, four (2%) were caused by S Typhi with QRDR mutations, compared with six (33%) of 18 cases between Sept 1 and Oct 31, 2019. This increase was associated with a preceding spike in ciprofloxacin prescriptions. Every additional prescription of ciprofloxacin given to study participants in the preceding month was associated with a 4·2% increase (95% CI 1·8-7·0) in the relative risk of isolating S Typhi with a QRDR mutation (p=0·0008). Phylogenetic analysis showed that S Typhi isolates with QRDR mutations from September and October, 2019, belonged to two distinct subclades encoding two different QRDR mutations, and were closely related (4-10 single-nucleotide polymorphisms) to susceptible S Typhi endemic to Blantyre. INTERPRETATION We postulate a causal relationship between increased ciprofloxacin prescriptions and an increase in fluoroquinolone non-susceptibility in S Typhi. Decreasing ciprofloxacin use by improving typhoid diagnostics, and reducing typhoid fever cases through the use of an efficacious vaccine, could help to limit the emergence of resistance. FUNDING Wellcome Trust, Bill & Melinda Gates Foundation, and National Institute for Health and Care Research (UK).
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Affiliation(s)
- Philip M Ashton
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK.
| | - Angeziwa Chunga Chirambo
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK; Department of Medical Laboratory Sciences, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - James E Meiring
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | | | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | - Niza Silungwe
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | | | - Happy Banda
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | - Robert S Heyderman
- Research Department of Infection, Division of Infection and Immunity, University College London, London, UK
| | - Zoe A Dyson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Peter MacPherson
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; School of Health & Wellbeing, University of Glasgow, Glasgow, UK
| | - Marc Y R Henrion
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Kathryn E Holt
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
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8
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Atlas HE, Conteh B, Islam MT, Jere KC, Omore R, Sanogo D, Schiaffino F, Yousafzai MT, Ahmed N, Awuor AO, Badji H, Cornick J, Feutz E, Galagan SR, Haidara FC, Horne B, Hossen MI, Hotwani A, Houpt ER, Jallow AF, Karim M, Keita AM, Keita Y, Khanam F, Liu J, Malemia T, Manneh A, McGrath CJ, Nasrin D, Ndalama M, Ochieng JB, Ogwel B, Paredes Olortegui M, Zegarra Paredes LF, Pinedo Vasquez T, Platts-Mills JA, Qudrat-E-Khuda S, Qureshi S, Hasan Rajib MN, Rogawski McQuade ET, Sultana S, Tennant SM, Tickell KD, Witte D, Peñataro Yori P, Cunliffe NA, Hossain MJ, Kosek MN, Kotloff KL, Qadri F, Qamar FN, Tapia MD, Pavlinac PB. Diarrhea Case Surveillance in the Enterics for Global Health Shigella Surveillance Study: Epidemiologic Methods. Open Forum Infect Dis 2024; 11:S6-S16. [PMID: 38532963 PMCID: PMC10962728 DOI: 10.1093/ofid/ofad664] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
Background Shigella is a leading cause of acute watery diarrhea, dysentery, and diarrhea-attributed linear growth faltering, a precursor to stunting and lifelong morbidity. Several promising Shigella vaccines are in development and field efficacy trials will require a consortium of potential vaccine trial sites with up-to-date Shigella diarrhea incidence data. Methods The Enterics for Global Health (EFGH) Shigella surveillance study will employ facility-based enrollment of diarrhea cases aged 6-35 months with 3 months of follow-up to establish incidence rates and document clinical, anthropometric, and financial consequences of Shigella diarrhea at 7 country sites (Mali, Kenya, The Gambia, Malawi, Bangladesh, Pakistan, and Peru). Over a 24-month period between 2022 and 2024, the EFGH study aims to enroll 9800 children (1400 per country site) between 6 and 35 months of age who present to local health facilities with diarrhea. Shigella species (spp.) will be identified and serotyped from rectal swabs by conventional microbiologic methods and quantitative polymerase chain reaction. Shigella spp. isolates will undergo serotyping and antimicrobial susceptibility testing. Incorporating population and healthcare utilization estimates from contemporaneous household sampling in the catchment areas of enrollment facilities, we will estimate Shigella diarrhea incidence rates. Conclusions This multicountry surveillance network will provide key incidence data needed to design Shigella vaccine trials and strengthen readiness for potential trial implementation. Data collected in EFGH will inform policy makers about the relative importance of this vaccine-preventable disease, accelerating the time to vaccine availability and uptake among children in high-burden settings.
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Affiliation(s)
- Hannah E Atlas
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Bakary Conteh
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Md Taufiqul Islam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Khuzwayo C Jere
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Medical Laboratory Sciences, Kamuzu University of Health Sciences, School of Life Sciences and Health Professions, Blantyre, Malawi
| | - Richard Omore
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Doh Sanogo
- Centre pour le Développement des Vaccins du Mali, Bamako, Mali
| | - Francesca Schiaffino
- Faculty of Veterinary Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
- Division of Infectious Diseases and International Health University of Virginia, School of Medicine, Charlottesville, Virginia, USA
| | | | - Naveed Ahmed
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Alex O Awuor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Henry Badji
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jennifer Cornick
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Erika Feutz
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Sean R Galagan
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | | | - Bri’Anna Horne
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Md Ismail Hossen
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Aneeta Hotwani
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Eric R Houpt
- Division of Infectious Diseases and International Health University of Virginia, School of Medicine, Charlottesville, Virginia, USA
| | - Abdoulie F Jallow
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mehrab Karim
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | | | - Youssouf Keita
- Centre pour le Développement des Vaccins du Mali, Bamako, Mali
| | - Farhana Khanam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Jie Liu
- School of Public Health, Qingdao University, Qingdao, China
| | | | - Alhagie Manneh
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Christine J McGrath
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Dilruba Nasrin
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | | | - Billy Ogwel
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | | | | | - James A Platts-Mills
- Division of Infectious Diseases and International Health University of Virginia, School of Medicine, Charlottesville, Virginia, USA
| | - Syed Qudrat-E-Khuda
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Sonia Qureshi
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Md Nazmul Hasan Rajib
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Shazia Sultana
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Sharon M Tennant
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kirkby D Tickell
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Desiree Witte
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Pablo Peñataro Yori
- Division of Infectious Diseases and International Health University of Virginia, School of Medicine, Charlottesville, Virginia, USA
| | - Nigel A Cunliffe
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - M Jahangir Hossain
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Margaret N Kosek
- Division of Infectious Diseases and International Health University of Virginia, School of Medicine, Charlottesville, Virginia, USA
| | - Karen L Kotloff
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Milagritos D Tapia
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Patricia B Pavlinac
- Department of Global Health, University of Washington, Seattle, Washington, USA
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9
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Martin LB, Khanam F, Qadri F, Khalil I, Sikorski MJ, Baker S. Vaccine value profile for Salmonella enterica serovar Paratyphi A. Vaccine 2023; 41 Suppl 2:S114-S133. [PMID: 37951691 DOI: 10.1016/j.vaccine.2023.01.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/27/2022] [Accepted: 01/23/2023] [Indexed: 11/14/2023]
Abstract
In Asia, there are an estimated 12 million annual cases of enteric fever, a potentially fatal systemic bacterial infection caused by Salmonella enterica serovars Typhi (STy) and Paratyphi A (SPA). The recent availability of typhoid conjugate vaccines (TCV), an increasing incidence of disease caused by SPA and growing antimicrobial resistance (AMR) across the genus Salmonella makes a bivalent STy/SPA vaccine a useful public health proposition. The uptake of a stand-alone paratyphoid vaccine is likely low thus, there is a pipeline of bivalent STy/SPA candidate vaccines. Several candidates are close to entering clinical trials, which if successful should facilitate a more comprehensive approach for enteric fever control. Additionally, the World Health Organization (WHO) has made advancing the development of vaccines that protect young children and working aged adults against both agents of enteric fever a priority objective. This "Vaccine Value Profile" (VVP) addresses information related predominantly to invasive disease caused by SPA prevalent in Asia. Information is included on stand-alone SPA candidate vaccines and candidate vaccines targeting SPA combined with STy. Out of scope for the first version of this VVP is a wider discussion on the development of a universal Salmonella combination candidate vaccine, addressing both enteric fever and invasive non-typhoidal Salmonella disease, for use globally. This VVP is a detailed, high-level assessment of existing, publicly available information to inform and contextualize the public health, economic, and societal potential of pipeline vaccines and vaccine-like products for SPA. Future versions of this VVP will be updated to reflect ongoing activities such as vaccine development strategies and "Full Vaccine Value Assessment" that will inform the value proposition of an SPA vaccine. This VVP was developed by an expert working group from academia, non-profit organizations, public-private partnerships, and multi-lateral organizations as well as in collaboration with stakeholders from the WHO South-East Asian Region. All contributors have extensive expertise on various elements of the VVP for SPA and collectively aimed to identify current research and knowledge gaps.
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Affiliation(s)
- Laura B Martin
- Independent Consultant (current affiliation US Pharmacopeia Convention), USA.
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Bangladesh.
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Bangladesh.
| | | | | | - Stephen Baker
- University of Cambridge School of Clinical Medicine, UK.
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10
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Aruta MG, Lari E, De Simone D, Semplici B, Semplici C, Dale H, Chirwa E, Kadwala I, Mbewe M, Banda H, Iturriza-Gomara M, Gordon M, Nyirenda T, Piu P, Pizza M, Berlanda Scorza F, Grappi S, Canals R, Rossi O. Characterization of Enzyme-Linked Immunosorbent Assay (ELISA) for Quantification of Antibodies against Salmonella Typhimurium and Salmonella Enteritidis O-Antigens in Human Sera. BIOTECH 2023; 12:54. [PMID: 37606441 PMCID: PMC10443281 DOI: 10.3390/biotech12030054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/23/2023] Open
Abstract
Nontyphoidal Salmonella (NTS) is a leading cause of morbidity and mortality caused by enteric pathogens worldwide in both children and adults, and vaccines are not yet available. The measurement of antigen-specific antibodies in the sera of vaccinated or convalescent individuals is crucial to understand the incidence of disease and the immunogenicity of vaccine candidates. A solid and standardized assay used to determine the level of specific anti-antigens IgG is therefore of paramount importance. In this work, we presented the characterization of a customized enzyme-linked immunosorbent assay (ELISA) with continuous readouts and a standardized definition of EU/mL. We assessed various performance parameters: standard curve accuracy, dilutional linearity, intermediate precision, specificity, limits of blanks, and quantification. The simplicity of the assay, its high sensitivity and specificity coupled with its low cost and the use of basic consumables and instruments without the need of high automation makes it suitable for transfer and application to different laboratories, including resource-limiting settings where the disease is endemic. This ELISA is, therefore, fit for purpose to be used for quantification of antibodies against Salmonella Typhimurium and Salmonella Enteritidis O-antigens in human samples, both for vaccine clinical trials and large sero-epidemiological studies.
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Affiliation(s)
- Maria Grazia Aruta
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
| | - Elisa Lari
- VisMederi S.r.l., 53100 Siena, Italy; (E.L.); (B.S.); (C.S.); (P.P.); (S.G.)
| | - Daniele De Simone
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
| | - Bianca Semplici
- VisMederi S.r.l., 53100 Siena, Italy; (E.L.); (B.S.); (C.S.); (P.P.); (S.G.)
| | - Claudia Semplici
- VisMederi S.r.l., 53100 Siena, Italy; (E.L.); (B.S.); (C.S.); (P.P.); (S.G.)
| | - Helen Dale
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Esmelda Chirwa
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Innocent Kadwala
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
| | - Maurice Mbewe
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
| | - Happy Banda
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
| | - Miren Iturriza-Gomara
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
| | - Melita Gordon
- Malawi Liverpool Wellcome Trust Programme, Blantyre 30096, Malawi; (H.D.); (E.C.); (I.K.); (M.M.); (H.B.); (M.G.)
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Tonney Nyirenda
- Pathology Department, Kamuzu University of Health Sciences, Blantyre 312225, Malawi;
| | - Pietro Piu
- VisMederi S.r.l., 53100 Siena, Italy; (E.L.); (B.S.); (C.S.); (P.P.); (S.G.)
| | - Mariagrazia Pizza
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
- Imperial College South Kensington Campus, London SW7 2AZ, UK
| | - Francesco Berlanda Scorza
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
| | - Silvia Grappi
- VisMederi S.r.l., 53100 Siena, Italy; (E.L.); (B.S.); (C.S.); (P.P.); (S.G.)
| | - Rocío Canals
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
| | - Omar Rossi
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., 53100 Siena, Italy; (M.G.A.); (D.D.S.); (M.I.-G.); (M.P.); (F.B.S.)
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11
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Fachrul M, Karkey A, Shakya M, Judd LM, Harshegyi T, Sim KS, Tonks S, Dongol S, Shrestha R, Salim A, Baker S, Pollard AJ, Khor CC, Dolecek C, Basnyat B, Dunstan SJ, Holt KE, Inouye M. Direct inference and control of genetic population structure from RNA sequencing data. Commun Biol 2023; 6:804. [PMID: 37532769 PMCID: PMC10397182 DOI: 10.1038/s42003-023-05171-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 07/24/2023] [Indexed: 08/04/2023] Open
Abstract
RNAseq data can be used to infer genetic variants, yet its use for estimating genetic population structure remains underexplored. Here, we construct a freely available computational tool (RGStraP) to estimate RNAseq-based genetic principal components (RG-PCs) and assess whether RG-PCs can be used to control for population structure in gene expression analyses. Using whole blood samples from understudied Nepalese populations and the Geuvadis study, we show that RG-PCs had comparable results to paired array-based genotypes, with high genotype concordance and high correlations of genetic principal components, capturing subpopulations within the dataset. In differential gene expression analysis, we found that inclusion of RG-PCs as covariates reduced test statistic inflation. Our paper demonstrates that genetic population structure can be directly inferred and controlled for using RNAseq data, thus facilitating improved retrospective and future analyses of transcriptomic data.
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Affiliation(s)
- Muhamad Fachrul
- Cambridge Baker Systems Genomics Initiative, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.
- Department of Clinical Pathology, University of Melbourne, Parkville, VIC, Australia.
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia.
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | - Louise M Judd
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Taylor Harshegyi
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Kar Seng Sim
- Genome Institute of Singapore, Singapore, Singapore
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | | | - Agus Salim
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC, Australia
- Department of Population Health, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | | | - Christiane Dolecek
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Michael Inouye
- Cambridge Baker Systems Genomics Initiative, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.
- Department of Clinical Pathology, University of Melbourne, Parkville, VIC, Australia.
- Cambridge Baker Systems Genomics Initiative, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK.
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
- British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK.
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, UK.
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12
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Saha T, Arisoyin AE, Bollu B, Ashok T, Babu A, Issani A, Jhaveri S, Avanthika C. Enteric Fever: Diagnostic Challenges and the Importance of Early Intervention. Cureus 2023; 15:e41831. [PMID: 37575696 PMCID: PMC10423039 DOI: 10.7759/cureus.41831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2023] [Indexed: 08/15/2023] Open
Abstract
Enteric fever is a systemic infection caused by highly virulent Salmonella enterica serovars: Typhi and Paratyphi. Diagnosis of enteric fever is challenging due to a wide variety of clinical features which overlap with other febrile illnesses. The current diagnostic methods are limited because of the suboptimal sensitivity of conventional tests like blood culture in detecting organisms and the invasive nature of bone marrow culture. It emphasizes the need to develop improved and more reliable diagnostic modalities. The rising rates of multidrug-resistant Salmonella strains call for an accurate understanding of the current management of the disease. Proper public health measures and large-scale immunization programs will help reduce the burden of the disease. A comprehensive surveillance system can help detect the chronic carrier state and is crucial in understanding antibiotic susceptibility patterns. We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar till May 2022. The following search words and medical subject headings (MeSH) were used: "enteric fever," "Salmonella Typhi," "multidrug-resistant Salmonella," chronic carrier state," "Salmonella detection, "and "typhoid vaccine." We reviewed the literature on clinical features, pathophysiology, new diagnostic tests, and interventions to prevent the disease. This article explores enteric fever and its various clinical features and addresses the emerging threat of multidrug resistance. It focuses on novel methods for diagnosis and prevention strategies, including vaccines and the use of surveillance systems employed across different parts of the world.
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Affiliation(s)
- Tias Saha
- Internal Medicine, Samorita General Hospital, Faridpur, BGD
- Internal Medicine, Diabetic Association Medical College, Faridpur, BGD
| | | | - Bhaswanth Bollu
- Emergency Medicine, All India Institute of Medical Sciences, New Delhi, IND
| | - Tejaswini Ashok
- Internal Medicine, Jagadguru Sri Shivarathreeshwara Medical College, Mysore, IND
| | - Athira Babu
- Pediatrics, Saudi German Hospital, Dubai, ARE
| | - Ali Issani
- Emergency Medicine, Aga Khan University, Karachi, PAK
| | - Sharan Jhaveri
- Internal Medicine, Nathiba Hargovandas Lakhmichand Municipal Medical College, Ahmedabad, IND
| | - Chaithanya Avanthika
- Pediatrics, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital Center, New York, USA
- Medicine and Surgery, Karnataka Institute of Medical Sciences, Hubli, IND
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13
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Cocker D, Sammarro M, Chidziwisano K, Elviss N, Jacob ST, Kajumbula H, Mugisha L, Musoke D, Musicha P, Roberts AP, Rowlingson B, Singer AC, Byrne RL, Edwards T, Lester R, Wilson CN, Hollihead B, Thomson NR, Jewell CP, Morse T, Feasey NA. Drivers of Resistance in Uganda and Malawi (DRUM): a protocol for the evaluation of One-Health drivers of Extended Spectrum Beta Lactamase (ESBL) resistance in Low-Middle Income Countries (LMICs). Wellcome Open Res 2023; 7:55. [PMID: 38817338 PMCID: PMC11137479 DOI: 10.12688/wellcomeopenres.17581.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2023] [Indexed: 06/01/2024] Open
Abstract
In sub-Saharan Africa (sSA), there is high morbidity and mortality from severe bacterial infection and this is compounded by antimicrobial resistance, in particular, resistance to 3rd-generation cephalosporins. This resistance is typically mediated by extended-spectrum beta lactamases (ESBLs). To interrupt ESBL transmission it will be important to investigate how human behaviour, water, sanitation, and hygiene (WASH) practices, environmental contamination, and antibiotic usage in both urban and rural settings interact to contribute to transmission of ESBL E. coli and ESBL K. pneumoniae between humans, animals, and the environment. Here we present the protocol for the Drivers of Resistance in Uganda and Malawi (DRUM) Consortium, in which we will collect demographic, geospatial, clinical, animal husbandry and WASH data from a total of 400 households in Uganda and Malawi. Longitudinal human, animal and environmental sampling at each household will be used to isolate ESBL E. coli and ESBL K. pneumoniae. This will be complimented by a Risks, Attitudes, Norms, Abilities and Self-Regulation (RANAS) survey and structured observations to understand the contextual and psychosocial drivers of regional WASH practices. Bacterial isolates and plate sweeps will be further characterised using a mixture of short-,long-read and metagenomic whole-genome sequencing. These datasets will be integrated into agent-based models to describe the transmission of EBSL resistance in Uganda and Malawi and allow us to inform the design of interventions for interrupting transmission of ESBL-bacteria.
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Affiliation(s)
- Derek Cocker
- Malawi-Liverpool Wellcome Trust Clinical Research Program, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Melodie Sammarro
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Centre for Health Informatics Computing and Statistics, Lancaster University, Lancaster, UK
| | - Kondwani Chidziwisano
- Centre for Water, Sanitation, Health and Appropriate Technology Development (WASHTED), Polytechnic, University of Malawi, Blantyre, Malawi
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
| | - Nicola Elviss
- Science Group, United Kingdom Health Security Agency, London, UK
| | - Shevin T. Jacob
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Global Health Security Department, Infectious Disease Institute, Makerere University, Kampala, Uganda
| | - Henry Kajumbula
- Department of Medical Microbiology, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Lawrence Mugisha
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda
- Conservation & Ecosystem Health Alliance, Kampala, Uganda
| | - David Musoke
- Department of Disease Control and Environmental Health, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Patrick Musicha
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Adam P. Roberts
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Barry Rowlingson
- Centre for Health Informatics Computing and Statistics, Lancaster University, Lancaster, UK
| | | | - Rachel L. Byrne
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Thomas Edwards
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Rebecca Lester
- Malawi-Liverpool Wellcome Trust Clinical Research Program, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Catherine N. Wilson
- Malawi-Liverpool Wellcome Trust Clinical Research Program, Blantyre, Malawi
- Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Beth Hollihead
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Nicholas R. Thomson
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Department of Pathogen Molecular Biology, London School of Tropical Medicine and Hygiene, London, UK
| | - Christopher P. Jewell
- Centre for Health Informatics Computing and Statistics, Lancaster University, Lancaster, UK
| | - Tracy Morse
- Centre for Water, Sanitation, Health and Appropriate Technology Development (WASHTED), Polytechnic, University of Malawi, Blantyre, Malawi
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
| | - Nicholas A. Feasey
- Malawi-Liverpool Wellcome Trust Clinical Research Program, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
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14
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Phillips MT, Antillon M, Bilcke J, Bar-Zeev N, Limani F, Debellut F, Pecenka C, Neuzil KM, Gordon MA, Thindwa D, Paltiel AD, Yaesoubi R, Pitzer VE. Cost-effectiveness analysis of typhoid conjugate vaccines in an outbreak setting: a modeling study. BMC Infect Dis 2023; 23:143. [PMID: 36890448 PMCID: PMC9993384 DOI: 10.1186/s12879-023-08105-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 02/20/2023] [Indexed: 03/10/2023] Open
Abstract
BACKGROUND Several prolonged typhoid fever epidemics have been reported since 2010 throughout eastern and southern Africa, including Malawi, caused by multidrug-resistant Salmonella Typhi. The World Health Organization recommends the use of typhoid conjugate vaccines (TCVs) in outbreak settings; however, current data are limited on how and when TCVs might be introduced in response to outbreaks. METHODOLOGY We developed a stochastic model of typhoid transmission fitted to data from Queen Elizabeth Central Hospital in Blantyre, Malawi from January 1996 to February 2015. We used the model to evaluate the cost-effectiveness of vaccination strategies over a 10-year time horizon in three scenarios: (1) when an outbreak is likely to occur; (2) when an outbreak is unlikely to occur within the next ten years; and (3) when an outbreak has already occurred and is unlikely to occur again. We considered three vaccination strategies compared to the status quo of no vaccination: (a) preventative routine vaccination at 9 months of age; (b) preventative routine vaccination plus a catch-up campaign to 15 years of age; and (c) reactive vaccination with a catch-up campaign to age 15 (for Scenario 1). We also explored variations in outbreak definitions, delays in implementation of reactive vaccination, and the timing of preventive vaccination relative to the outbreak. RESULTS Assuming an outbreak occurs within 10 years, we estimated that the various vaccination strategies would prevent a median of 15-60% of disability-adjusted life-years (DALYs). Reactive vaccination was the preferred strategy for WTP values of $0-300 per DALY averted. For WTP values > $300, introduction of preventative routine TCV immunization with a catch-up campaign was the preferred strategy. Routine vaccination with a catch-up campaign was cost-effective for WTP values above $890 per DALY averted if no outbreak occurs and > $140 per DALY averted if implemented after the outbreak has already occurred. CONCLUSIONS Countries for which the spread of antimicrobial resistance is likely to lead to outbreaks of typhoid fever should consider TCV introduction. Reactive vaccination can be a cost-effective strategy, but only if delays in vaccine deployment are minimal; otherwise, introduction of preventive routine immunization with a catch-up campaign is the preferred strategy.
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Affiliation(s)
- Maile T Phillips
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., P.O. Box 208034, New Haven, CT, 06520-8034, USA
| | - Marina Antillon
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Joke Bilcke
- Center for Health Economics Research and Modeling Infectious Diseases, University of Antwerp, Antwerp, Belgium
| | - Naor Bar-Zeev
- International Vaccine Access Center, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Fumbani Limani
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi.,Kamuzu University of Health Sciences, Blantyre, Malawi
| | | | - Clint Pecenka
- Center for Vaccine Innovation and Access, PATH, Seattle, WA, USA
| | - Kathleen M Neuzil
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Melita A Gordon
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi.,Kamuzu University of Health Sciences, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Deus Thindwa
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi.,Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - A David Paltiel
- Department of Health Policy, Yale School of Public Health, New Haven, CT, USA
| | - Reza Yaesoubi
- Department of Health Policy, Yale School of Public Health, New Haven, CT, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., P.O. Box 208034, New Haven, CT, 06520-8034, USA.
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15
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Development and Characterization of a Luminescence-Based High-Throughput Serum Bactericidal Assay (L-SBA) to Assess Bactericidal Activity of Human Sera against Nontyphoidal Salmonella. Methods Protoc 2022; 5:mps5060100. [PMID: 36548142 PMCID: PMC9783057 DOI: 10.3390/mps5060100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/30/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Salmonella Typhimurium and Salmonella Enteritidis are leading causative agents of invasive nontyphoidal Salmonella (iNTS) disease, which represents one of the major causes of death and morbidity in sub-Saharan Africa, still partially underestimated. Large sero-epidemiological studies are necessary to unravel the burden of disease and guide the introduction of vaccines that are not yet available. Even if no correlate of protection has been determined so far for iNTS, the evaluation of complement-mediated functionality of antibodies generated towards natural infection or elicited upon vaccination may represent a big step towards this achievement. Here we present the setup and the intra-laboratory characterization in terms of repeatability, intermediate precision, linearity, and specificity of a high-throughput luminescence-based serum bactericidal assay (L-SBA). This method could be useful to perform sero-epidemiological studies across iNTS endemic countries and for evaluation of antibodies raised against iNTS vaccine candidates in upcoming clinical trials.
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16
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Swarthout TD, Henrion MYR, Thindwa D, Meiring JE, Mbewe M, Kalizang'Oma A, Brown C, Msefula J, Moyo B, Mataya AA, Barnaba S, Pearce E, Gordon M, Goldblatt D, French N, Heyderman RS. Waning of antibody levels induced by a 13-valent pneumococcal conjugate vaccine, using a 3 + 0 schedule, within the first year of life among children younger than 5 years in Blantyre, Malawi: an observational, population-level, serosurveillance study. THE LANCET. INFECTIOUS DISEASES 2022; 22:1737-1747. [PMID: 36029796 PMCID: PMC10555849 DOI: 10.1016/s1473-3099(22)00438-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Pneumococcal conjugate vaccines (PCVs) induce serotype-specific IgG antibodies, effectively reducing vaccine-serotype carriage and invasive pneumococcal disease (IPD). IgG production wanes approximately 1 month after vaccination in absence of serotype-specific exposure. With uncertainty surrrounding correlate of protection (CoP) estimates and with persistent vaccine-serotype carriage and vaccine-serotype IPD after PCV13 introduction, we aimed to profile population-level immunogenicity among children younger than 5 years in Blantyre, Malawi. METHODS For this serosurveillance study, we used a random subset of samples from a prospective population-based serosurvey in Blantyre, Malawi, done between Dec 16, 2016, and June 27, 2018. Sample selection was based on age category optimisation among children younger than 5 years, adequate sample volume, and available budget. We measured serotype-specific IgGs against the 13 vaccine serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) and two non-vaccine serotypes (12F and 33F), as well as IgGs against three pneumococcal proteins (PsaA, NanA, and Ply), using ELISA and a direct-binding electrochemiluminescence-based multiplex assay. We estimated population-level, serotype-specific immunogenicity profiles using a linear spline regression model. Analyses included samples stratified to 20 3-month age strata (eg, age <3 months to 57-59 months). FINDINGS We evaluated 638 plasma samples: 556 primary samples and 82 unique secondary samples (each linked to one primary sample). Immunogenicity profiles revealed a consistent pattern among vaccine serotypes except serotype 3: a vaccine-induced IgG peak followed by waning to a nadir and subsequent increase in titre. For serotype 3, we observed no apparent vaccine-induced increase. Heterogeneity in parameters included age range at post-vaccination nadir (from 11·2 months [19A] to 27·3 months [7F]). The age at peak IgG titre ranged from 2·69 months (5) to 6·64 months (14). Titres dropped below CoPs against IPD among nine vaccine serotypes (1, 3, 4, 5, 6B, 7F, 9V, 18C, and 23F) and below CoPs against carriage for ten vaccine serotypes (1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F). Increasing antibody concentrations among older children and seroincident events were consistent with ongoing vaccine-serotype exposure. INTERPRETATION A 3 + 0 PCV13 schedule with high uptake has not led to sustained population-level antibody immunity beyond the first year of life. Indeed, post-vaccine antibody concentrations dropped below putative CoPs for several vaccine serotypes, potentially contributing to persistent vaccine-serotype carriage and residual vaccine-serotype IPD in Malawi and other similar settings. Policy decisions should consider alternative vaccine strategies, including a booster dose, to achieve sustained vaccine-induced antibody titres, and thus control. FUNDING Bill & Melinda Gates Foundation, Wellcome UK, and National Institute for Health and Care Research.
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Affiliation(s)
- Todd D Swarthout
- National Institute for Health and Care Research Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, UK; Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi.
| | - Marc Y R Henrion
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Deus Thindwa
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - James E Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Akuzike Kalizang'Oma
- National Institute for Health and Care Research Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, UK; Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Comfort Brown
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Jacquline Msefula
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Faculty of Medicine, University of Amsterdam, Amsterdam, Netherlands
| | - Brewster Moyo
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Andrew A Mataya
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Susanne Barnaba
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Chancellor College, University of Malawi, Blantyre, Malawi
| | - Emma Pearce
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Melita Gordon
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - David Goldblatt
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Neil French
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Robert S Heyderman
- National Institute for Health and Care Research Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, UK
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17
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Wolf AS, Mitsi E, Jones S, Jochems SP, Roalfe L, Thindwa D, Meiring JE, Msefula J, Bonomali F, Makhaza Jere T, Mbewe M, Collins AM, Gordon SB, Gordon MA, Ferreira DM, French N, Goldblatt D, Heyderman RS, Swarthout TD. Quality of antibody responses by adults and young children to 13-valent pneumococcal conjugate vaccination and Streptococcus pneumoniae colonisation. Vaccine 2022; 40:7201-7210. [PMID: 36210249 PMCID: PMC10615833 DOI: 10.1016/j.vaccine.2022.09.069] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/15/2022] [Accepted: 09/22/2022] [Indexed: 11/18/2022]
Abstract
Childhood pneumococcal conjugate vaccine (PCV) protects against invasive pneumococcal disease caused by vaccine-serotype (VT) Streptococcus pneumoniae by generating opsonophagocytic anti-capsular antibodies, but how vaccination protects against and reduces VT carriage is less well understood. Using serological samples from PCV-vaccinated Malawian individuals and a UK human challenge model, we explored whether antibody quality (IgG subclass, opsonophagocytic killing, and avidity) is associated with protection from carriage. Following experimental challenge of adults with S. pneumoniae serotype 6B, 3/21 PCV13-vaccinees were colonised with pneumococcus compared to 12/24 hepatitis A-vaccinated controls; PCV13-vaccination induced serotype-specific IgG, IgG1, and IgG2, and strong opsonophagocytic responses. However, there was no clear relationship between antibody quality and protection from carriage or carriage intensity after vaccination. Similarly, among PCV13-vaccinated Malawian infants there was no relationship between serotype-specific antibody titre or quality and carriage through exposure to circulating serotypes. Although opsonophagocytic responses were low in infants, antibody titre and avidity to circulating serotypes 19F and 6A were maintained or increased with age. These data suggest a complex relationship between antibody-mediated immunity and pneumococcal carriage, and that PCV13-driven antibody quality may mature with age and exposure.
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Affiliation(s)
- Asia-Sophia Wolf
- NIHR Global Health Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, UK
| | - Elena Mitsi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Scott Jones
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Simon P. Jochems
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Lucy Roalfe
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Deus Thindwa
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - James E. Meiring
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, UK
| | | | | | | | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | - Andrea M. Collins
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Liverpool University Hospitals Foundation Trust, Liverpool, UK
| | | | - Melita A. Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
- Kamuzu University of Health Sciences, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Daniela M. Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Neil French
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - David Goldblatt
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Robert S. Heyderman
- NIHR Global Health Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, UK
| | - Todd D. Swarthout
- NIHR Global Health Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, UK
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
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18
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Estimating the economic burden of typhoid in children and adults in Blantyre, Malawi: A costing cohort study. PLoS One 2022; 17:e0277419. [PMID: 36417455 PMCID: PMC9683590 DOI: 10.1371/journal.pone.0277419] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 10/26/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Typhoid causes preventable death and disease. The World Health Organization recommends Typhoid Conjugate Vaccine for endemic countries, but introduction decisions depend on cost-effectiveness. We estimated household and healthcare economic burdens of typhoid in Blantyre, Malawi. METHODS In a prospective cohort of culture-confirmed typhoid cases at two primary- and a referral-level health facility, we collected direct medical, non-medical costs (2020 U.S. dollars) to healthcare provider, plus indirect costs to households. RESULTS From July 2019-March 2020, of 109 cases, 63 (58%) were <15 years old, 44 (40%) were inpatients. Mean hospitalization length was 7.7 days (SD 4.1). For inpatients, mean total household and provider costs were $93.85 (95%CI: 68.87-118.84) and $296.52 (95%CI: 225.79-367.25), respectively. For outpatients, these costs were $19.05 (95%CI: 4.38-33.71) and $39.65 (95%CI: 33.93-45.39), respectively. Household costs were due mainly to direct non-medical and indirect costs, medical care was free. Catastrophic illness cost, defined as cost >40% of non-food monthly household expenditure, occurred in 48 (44%) households. CONCLUSIONS Typhoid can be economically catastrophic for families, despite accessible free medical care. Typhoid is costly for government healthcare provision. These data make an economic case for TCV introduction in Malawi and the region and will be used to derive vaccine cost-effectiveness.
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19
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Cocker D, Sammarro M, Chidziwisano K, Elviss N, Jacob ST, Kajumbula H, Mugisha L, Musoke D, Musicha P, Roberts AP, Rowlingson B, Singer AC, Byrne RL, Edwards T, Lester R, Wilson C, Hollihead B, Thomson N, Jewell CP, Morse T, Feasey N. Drivers of Resistance in Uganda and Malawi (DRUM): a protocol for the evaluation of One-Health drivers of Extended Spectrum Beta Lactamase (ESBL) resistance in Low-Middle Income Countries (LMICs). Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17581.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In sub-Saharan Africa (sSA), there is high morbidity and mortality from severe bacterial infection and this is compounded by antimicrobial resistance, in particular, resistance to 3rd-generation cephalosporins. This resistance is typically mediated by extended-spectrum beta lactamases (ESBLs). To interrupt ESBL transmission it will be important to investigate how human behaviour, water, sanitation, and hygiene (WASH) practices, environmental contamination, and antibiotic usage in both urban and rural settings interact to contribute to transmission of ESBL E. coli and ESBL K. pneumoniae between humans, animals, and the environment. Here we present the protocol for the Drivers of Resistance in Uganda and Malawi (DRUM) Consortium, in which we will collect demographic, geospatial, clinical, animal husbandry and WASH data from a total of 400 households in Uganda and Malawi. Longitudinal human, animal and environmental sampling at each household will be used to isolate ESBL E. coli and ESBL K. pneumoniae. This will be complimented by a Risks, Attitudes, Norms, Abilities and Self-Regulation (RANAS) survey and structured observations to understand the contextual and psychosocial drivers of regional WASH practices. Bacterial isolates and plate sweeps will be further characterised using a mixture of short-,long-read and metagenomic whole-genome sequencing. These datasets will be integrated into agent-based models to describe the transmission of EBSL resistance in Uganda and Malawi and allow us to inform the design of interventions for interrupting transmission of ESBL-bacteria.
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20
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Debellut F, Mkisi R, Masoo V, Chisema M, Mwagomba D, Mtenje M, Limani F, Mategula D, Zimba B, Pecenka C. Projecting the cost of introducing typhoid conjugate vaccine (TCV) in the national immunization program in Malawi using a standardized costing framework. Vaccine 2022; 40:1741-1746. [PMID: 35153097 PMCID: PMC8917043 DOI: 10.1016/j.vaccine.2022.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 11/19/2022]
Abstract
Background There is a substantial typhoid burden in sub-Saharan Africa, and TCV has been introduced in two African countries to date. Decision-makers in Malawi decided to introduce TCV and applied for financial support from Gavi, the Vaccine Alliance in 2020. The current plan is to introduce TCV as part of the national immunization program in late 2022. The introduction will include a nationwide campaign targeting all children aged 9 months to 15 years. Following the campaign, TCV will be provided through routine immunization at 9 months. This study aims to estimate the cost of TCV introduction and recurrent delivery as part of the national immunization program. Methods This costing analysis is conducted from the government's perspective and focuses on projecting the incremental cost of TCV introduction and delivery for Malawi’s existing immunization program before vaccine introduction. The study uses a costing tool developed by Levin & Morgan through a partnership between the International Vaccine Institute and the World Health Organization and leverages primary and secondary data collected through key informant interviews with representatives of the Malawi Expanded Programme on Immunization team at various levels. Results The total financial and economic costs of TCV introduction over three years in Malawi are projected to be US$8.5 million and US$29.8 million, respectively. More than two-thirds of the total cost is made up of recurrent costs. Major cost drivers include the procurement of vaccines and injection supplies and service delivery costs. Without vaccine cost, we estimate the cost per child immunized to be substantially lower than US$1. Discussion Findings from this analysis may be used to assess the economic implications of introducing TCV in Malawi. Major cost drivers highlighted by the analysis may also inform decision-makers in the region as they assess the value and feasibility of TCV introduction in their national immunization program.
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Affiliation(s)
- Frédéric Debellut
- Center for Vaccine Innovation and Access, PATH, Geneva, Switzerland.
| | - Rouden Mkisi
- Center for Vaccine Innovation and Access, PATH, Lilongwe, Malawi
| | - Vincent Masoo
- Health Management Information System, Mzuzu Central Hospital, Mzuzu, Malawi
| | - Mike Chisema
- Expanded Programme on Immunization, Ministry of Health, Lilongwe, Malawi
| | - Dennis Mwagomba
- Expanded Programme on Immunization, Ministry of Health, Lilongwe, Malawi
| | - Mphatso Mtenje
- Expanded Programme on Immunization, Ministry of Health, Lilongwe, Malawi
| | - Fumbani Limani
- Malawi-Liverpool-Wellcome Trust/College of Medicine, Chichiri, Blantyre, Malawi
| | - Donnie Mategula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital Blantyre, Malawi
| | | | - Clint Pecenka
- Center for Vaccine Innovation and Access, PATH, Seattle, USA
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21
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Meiring JE, Shakya M, Khanam F, Voysey M, Phillips MT, Tonks S, Thindwa D, Darton TC, Dongol S, Karkey A, Zaman K, Baker S, Dolecek C, Dunstan SJ, Dougan G, Holt KE, Heyderman RS, Qadri F, Pitzer VE, Basnyat B, Gordon MA, Clemens J, Pollard AJ. Burden of enteric fever at three urban sites in Africa and Asia: a multicentre population-based study. THE LANCET GLOBAL HEALTH 2021; 9:e1688-e1696. [PMID: 34798028 PMCID: PMC8609278 DOI: 10.1016/s2214-109x(21)00370-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/29/2021] [Accepted: 07/30/2021] [Indexed: 12/13/2022] Open
Abstract
Background Enteric fever is a serious public health concern in many low-income and middle-income countries. Numerous data gaps exist concerning the epidemiology of Salmonella enterica serotype Typhi (S Typhi) and Salmonella enterica serotype Paratyphi (S Paratyphi), which are the causative agents of enteric fever. We aimed to determine the burden of enteric fever in three urban sites in Africa and Asia. Methods In this multicentre population-based study, we did a demographic census at three urban sites in Africa (Blantyre, Malawi) and Asia (Kathmandu, Nepal and Dhaka, Bangladesh) between June 1, 2016, and Sept 25, 2018. Households were selected randomly from the demographic census. Participants from within the geographical census area presenting to study health-care facilities were approached for recruitment if they had a history of fever for 72 h or more (later changed to >48 h) or temperature of 38·0°C or higher. Facility-based passive surveillance was done between Nov 11, 2016, and Dec 31, 2018, with blood-culture collection for febrile illness. We also did a community-based serological survey to obtain data on Vi-antibody defined infections. We calculated crude incidence for blood-culture-confirmed S Typhi and S Paratyphi infection, and calculated adjusted incidence and seroincidence of S Typhi blood-culture-confirmed infection. Findings 423 618 individuals were included in the demographic census, contributing 626 219 person-years of observation for febrile illness surveillance. 624 S Typhi and 108 S Paratyphi A isolates were collected from the blood of 12 082 febrile patients. Multidrug resistance was observed in 44% S Typhi isolates and fluoroquinolone resistance in 61% of S Typhi isolates. In Blantyre, the overall crude incidence of blood-culture confirmed S Typhi was 58 cases per 100 000 person-years of observation (95% CI 48–70); the adjusted incidence was 444 cases per 100 000 person-years of observation (95% credible interval [CrI] 347–717). The corresponding rates were 74 (95% CI 62–87) and 1062 (95% CrI 683–1839) in Kathmandu, and 161 (95% CI 145–179) and 1135 (95% CrI 898–1480) in Dhaka. S Paratyphi was not found in Blantyre; overall crude incidence of blood-culture-confirmed S Paratyphi A infection was 6 cases per 100 000 person-years of observation (95% CI 3–11) in Kathmandu and 42 (95% CI 34–52) in Dhaka. Seroconversion rates for S Typhi infection per 100 000 person-years estimated from anti-Vi seroconversion episodes in serological surveillance were 2505 episodes (95% CI 1605–3727) in Blantyre, 7631 (95% CI 5913–9691) in Kathmandu, and 3256 (95% CI 2432–4270) in Dhaka. Interpretation High disease incidence and rates of antimicrobial resistance were observed across three different transmission settings and thus necessitate multiple intervention strategies to achieve global control of these pathogens. Funding Wellcome Trust and the Bill & Melinda Gates Foundation.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK.
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | - Farhana Khanam
- International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Maile T Phillips
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Deus Thindwa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; College of Medicine, University of Malawi, Blantyre, Malawi
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | - Abilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Patan Academy of Health Sciences, Patan Hospital, Lalitpur, Nepal
| | - K Zaman
- International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Christiane Dolecek
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK; Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Robert S Heyderman
- National Institute for Health Research Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
| | - Firdausi Qadri
- International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal; Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; College of Medicine, University of Malawi, Blantyre, Malawi; Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - John Clemens
- International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
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22
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Phillips MT, Meiring JE, Voysey M, Warren JL, Baker S, Basnyat B, Clemens JD, Dolecek C, Dunstan SJ, Dougan G, Gordon MA, Thindwa D, Heyderman RS, Holt KE, Qadri F, Pollard AJ, Pitzer VE. A Bayesian approach for estimating typhoid fever incidence from large-scale facility-based passive surveillance data. Stat Med 2021; 40:5853-5870. [PMID: 34428309 PMCID: PMC9291985 DOI: 10.1002/sim.9159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 12/04/2022]
Abstract
Decisions about typhoid fever prevention and control are based on estimates of typhoid incidence and their uncertainty. Lack of specific clinical diagnostic criteria, poorly sensitive diagnostic tests, and scarcity of accurate and complete datasets contribute to difficulties in calculating age‐specific population‐level typhoid incidence. Using data from the Strategic Typhoid Alliance across Africa and Asia program, we integrated demographic censuses, healthcare utilization surveys, facility‐based surveillance, and serological surveillance from Malawi, Nepal, and Bangladesh to account for under‐detection of cases. We developed a Bayesian approach that adjusts the count of reported blood‐culture‐positive cases for blood culture detection, blood culture collection, and healthcare seeking—and how these factors vary by age—while combining information from prior published studies. We validated the model using simulated data. The ratio of observed to adjusted incidence rates was 7.7 (95% credible interval [CrI]: 6.0‐12.4) in Malawi, 14.4 (95% CrI: 9.3‐24.9) in Nepal, and 7.0 (95% CrI: 5.6‐9.2) in Bangladesh. The probability of blood culture collection led to the largest adjustment in Malawi, while the probability of seeking healthcare contributed the most in Nepal and Bangladesh; adjustment factors varied by age. Adjusted incidence rates were within or below the seroincidence rate limits of typhoid infection. Estimates of blood‐culture‐confirmed typhoid fever without these adjustments results in considerable underestimation of the true incidence of typhoid fever. Our approach allows each phase of the reporting process to be synthesized to estimate the adjusted incidence of typhoid fever while correctly characterizing uncertainty, which can inform decision‐making for typhoid prevention and control.
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Affiliation(s)
- Maile T Phillips
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK.,Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - Joshua L Warren
- Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - John D Clemens
- International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Christiane Dolecek
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Melita A Gordon
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Deus Thindwa
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert S Heyderman
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London
| | - Firdausi Qadri
- International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
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23
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Stockdale AJ, Meiring JE, Shawa IT, Thindwa D, Silungwe NM, Mbewe M, Kachala R, Kreuels B, Patel P, Patel P, Henrion MYR, Bar-Zeev N, Swarthout TD, Heyderman RS, Gordon SB, Geretti AM, Gordon MA. Hepatitis B vaccination impact and the unmet need for antiviral treatment in Blantyre, Malawi. J Infect Dis 2021; 226:871-880. [PMID: 34752631 PMCID: PMC9470106 DOI: 10.1093/infdis/jiab562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hepatitis B is the leading cause of cirrhosis and liver cancer in sub-Saharan Africa. To reduce hepatitis-associated mortality, antiviral treatment programmes are needed. We estimated prevalence, vaccine impact and need for antiviral treatment in Blantyre, Malawi to inform an effective public health response. METHODS We conducted a household study in Blantyre in 2016-2018. We selected individuals from a census using random sampling and estimated age-sex-standardised HBsAg seroprevalence. Impact of infant hepatitis B vaccination, which began in 2002, was estimated by binomial log-linear regression comparing individuals born before and after vaccine implementation. In HBsAg-positive adults, eligibility for antiviral therapy was assessed. RESULTS Of 97,386 censused individuals, 6,073 (median age 18 years; 56.7% female) were sampled. HBsAg seroprevalence was 5.1% (95% CI 4.3-6.1) among adults and 0.3% (0.1-0.6) among children born after vaccine introduction. Estimated vaccine impact was 95.8% (70.3-99.4). Of HBsAg-positive adults, 26% were HIV-positive. Among HIV-negative individuals, 3%, 6% and 9% were eligible for hepatitis B treatment by WHO, European and American hepatology association criteria, respectively. CONCLUSIONS Infant HBV vaccination has been highly effective in reducing HBsAg prevalence in urban Malawi. Up to 9% of HBsAg-positive HIV-negative adults are eligible, but have an unmet need, for antiviral therapy.
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Affiliation(s)
- Alexander J Stockdale
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - James E Meiring
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
| | - Isaac T Shawa
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,University of Malawi College of Medicine, Faculty of Biomedical Science and Health Professions Blantyre, Malawi
| | - Deus Thindwa
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi
| | - Rabson Kachala
- Malawi Ministry of Health, Capitol Hill, Lilongwe, Malawi
| | - Benno Kreuels
- University of Malawi College of Medicine, Faculty of Medicine, Blantyre, Malawi.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and.,1st Department of Medicine, University Medical Centre, Hamburg-Eppendorf, Hamburg, Germany
| | | | - Priyanka Patel
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi
| | - Marc Y R Henrion
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Naor Bar-Zeev
- International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Todd D Swarthout
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,NIHR Global Health Research Unit on Mucosal Pathogens, Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Robert S Heyderman
- NIHR Global Health Research Unit on Mucosal Pathogens, Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Stephen B Gordon
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Anna Maria Geretti
- Department of Infectious Diseases, Fondazione PTV, Faculty of Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Programme, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
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24
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Khanam F, Darton TC, Meiring JE, Sarker PK, Biswas PK, Bhuiyan MAI, Rajib NH, Tonks S, Pollard AJ, Clemens JD, Qadri F. Salmonella Typhi stool shedding by enteric fever patients and asymptomatic chronic carriers in an endemic urban setting. J Infect Dis 2021; 224:S759-S763. [PMID: 34586391 PMCID: PMC8687075 DOI: 10.1093/infdis/jiab476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The burden of Salmonella Typhi shedding in stool and its contribution to transmission in endemic settings is unknown. During passive surveillance S. Typhi shedding was seen during convalescence in 332 bacteremic typhoid patients although none persisted at one-year follow-up. Anti-Vi-IgG titres were measured in age-stratified cohort of serosurveillance participants. Systematic stool sampling of 303 participants with high anti-Vi-IgG titres identified one asymptomatic carrier shedding. These findings suggest ongoing S. Typhi transmission in this setting is more likely to occur from acute convalescent cases although better approaches are needed to identify true chronic carriers in the community to enable typhoid elimination.
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Affiliation(s)
- Farhana Khanam
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh.,School of Medical Science, Griffith University, Gold Coast, Australia
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, and the Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, UK
| | - James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Protup Kumer Sarker
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Prasanta Kumar Biswas
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Md Amirul Islam Bhuiyan
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Nazmul Hasan Rajib
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - John D Clemens
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
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25
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Birkhold M, Mwisongo A, Pollard AJ, Neuzil KM. Typhoid conjugate vaccine in Africa and Asia: Status of clinical evaluation and vaccine introduction. J Infect Dis 2021; 224:S781-S787. [PMID: 34528085 PMCID: PMC8687070 DOI: 10.1093/infdis/jiab449] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The disease burden of typhoid fever remains high in endemic areas in Asia and Africa, especially in children. Recent clinical trials conducted by the Typhoid Vaccine Acceleration Consortium show typhoid conjugate vaccine (TCV) to be safe, immunogenic, and efficacious at preventing blood culture-confirmed typhoid fever in African and Asian children. Pakistan, Liberia, and Zimbabwe recently introduced TCV through campaigns and routine childhood immunizations, providing protection for this vulnerable population. It is essential to continue this momentum while simultaneously filling data gaps - including typhoid complications - to inform decision-making on TCV introduction. A multidisciplinary approach including surveillance, water, sanitation, and hygiene investments, and large-scale TCV introduction is needed to decrease the burden and mortality of typhoid fever.
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Affiliation(s)
- Megan Birkhold
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Aziza Mwisongo
- Center for Vaccine Innovation and Access, PATH
, Seattle, Washington, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Correspondence: Kathleen M. Neuzil, MD, MPH, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W Baltimore Street, Room 480, Baltimore, MD 21201 ()
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26
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Guevara PD, Maes M, Thanh DP, Duarte C, Rodriguez EC, Montaño LA, Dan THN, Nguyen TNT, Carey ME, Campos J, Chinen I, Perez E, Baker S. A genomic snapshot of Salmonella enterica serovar Typhi in Colombia. PLoS Negl Trop Dis 2021; 15:e0009755. [PMID: 34529660 PMCID: PMC8478212 DOI: 10.1371/journal.pntd.0009755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 09/28/2021] [Accepted: 08/24/2021] [Indexed: 11/23/2022] Open
Abstract
Little is known about the genetic diversity of Salmonella enterica serovar Typhi (S. Typhi) circulating in Latin America. It has been observed that typhoid fever is still endemic in this part of the world; however, a lack of standardized blood culture surveillance across Latin American makes estimating the true disease burden problematic. The Colombian National Health Service established a surveillance system for tracking bacterial pathogens, including S. Typhi, in 2006. Here, we characterized 77 representative Colombian S. Typhi isolates collected between 1997 and 2018 using pulse field gel electrophoresis (PFGE; the accepted genotyping method in Latin America) and whole genome sequencing (WGS). We found that the main S. Typhi clades circulating in Colombia were clades 2.5 and 3.5. Notably, the sequenced S. Typhi isolates from Colombia were closely related in a global phylogeny. Consequently, these data suggest that these are endemic clades circulating in Colombia. We found that AMR in S. Typhi in Colombia was uncommon, with a small subset of organisms exhibiting mutations associated with reduced susceptibility to fluoroquinolones. This is the first time that S. Typhi isolated from Colombia have been characterized by WGS, and after comparing these data with those generated using PFGE, we conclude that PFGE is unsuitable for tracking S. Typhi clones and mapping transmission. The genetic diversity of pathogens such as S. Typhi is limited in Latin America and should be targeted for future surveillance studies incorporating WGS.
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Affiliation(s)
| | - Mailis Maes
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Carolina Duarte
- Grupo de Microbiología, Instituto Nacional de Salud, Bogotá, Colombia
| | | | | | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - To Nguyen Thi Nguyen
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Megan E. Carey
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Josefina Campos
- Red Pulsenet Latinoamérica y el Caribe, INEI-ANLIS “Dr Carlos Malbran, Buenos Aires, Argentina
| | - Isabel Chinen
- Red Pulsenet Latinoamérica y el Caribe, INEI-ANLIS “Dr Carlos Malbran, Buenos Aires, Argentina
| | - Enrique Perez
- Health Emergencies Department, Pan American Health Organization/World Health Organization, PAHO/WHO, Washington DC, United States of America
| | - Stephen Baker
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
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27
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Stockdale AJ, Silungwe NM, Shawa IT, Kreuels B, Gordon MA, Geretti AM. Diagnostic performance evaluation of hepatitis B e antigen rapid diagnostic tests in Malawi. BMC Infect Dis 2021; 21:487. [PMID: 34044776 PMCID: PMC8157469 DOI: 10.1186/s12879-021-06134-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/19/2021] [Indexed: 12/18/2022] Open
Abstract
Background The World Health Organization (WHO) has targeted a reduction in viral hepatitis-related mortality by 65% and incidence by 90% by 2030, necessitating enhanced hepatitis B treatment and prevention programmes in low- and middle-income countries. Hepatitis B e antigen (HBeAg) status is used in the assessment of eligibility for antiviral treatment and for prevention of mother-to-child transmission (PMTCT). Accordingly, the WHO has classified HBeAg rapid diagnostic tests (RDTs) as essential medical devices. Methods We assessed the performance characteristics of three commercially available HBeAg RDTs (SD Bioline, Alere, South Africa; Creative Diagnostics, USA; and Biopanda Reagents, UK) in two hepatitis B surface antigen-positive cohorts in Blantyre, Malawi: participants of a community study (n = 100) and hospitalised patients with cirrhosis or hepatocellular carcinoma (n = 94). Two investigators, blinded to the reference test result, independently assessed each assay. We used an enzyme-linked immunoassay (Monolisa HBeAg, Bio-Rad, France) as a reference test and quantified HBeAg concentration using dilutions of the WHO HBeAg standard. We related the findings to HBV DNA levels, and evaluated treatment eligibility using the TREAT-B score. Results Among 194 HBsAg positive patients, median age was 37 years, 42% were femaleand 26% were HIV co-infected. HBeAg prevalence was 47/194 (24%). The three RDTs showed diagnostic sensitivity of 28% (95% CI 16–43), 53% (38–68) and 72% (57–84) and specificity of 96–100% for detection of HBeAg. Overall inter-rater agreement κ statistic was high at 0.9–1.0. Sensitivity for identifying patients at the threshold where antiviral treatment is recommended for PMTCT, with HBV DNA > 200,000 IU/ml (39/194; 20%), was 22, 49 and 54% respectively. Using the RDTs in place of the reference HBeAg assay resulted in 3/43 (9%), 5/43 (12%) and 8/43 (19%) of patients meeting the TREAT-B treatment criteria being misclassified as ineligible for treatment. A relationship between HBeAg concentration and HBeAg detection by RDT was observed. A minimum HBeAg concentration of 2.2–3.1 log10IU/ml was required to yield a reactive RDT. Conclusions Commercially available HBeAg RDTs lack sufficient sensitivity to accurately classify hepatitis B patients in Malawi. This has implications for hepatitis B public health programs in sub-Saharan Africa. Alternative diagnostic assays are recommended. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-06134-3.
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Affiliation(s)
- Alexander J Stockdale
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi. .,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK.
| | | | - Isaac Thom Shawa
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.,University of Malawi College of Medicine, Blantyre, Malawi
| | - Benno Kreuels
- University of Malawi College of Medicine, Blantyre, Malawi.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,First Department of Medicine, University Medical Centre, Hamburg-Eppendorf, Hamburg, Germany
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
| | - Anna Maria Geretti
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
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28
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Khanam F, Darton TC, Ross AGP, Zaman K, Pollard AJ, Clemens JD, Qadri F. Case Report: Typhoid Fever Complicated by Ileal Perforation in an Urban Slum of Dhaka, Bangladesh. Am J Trop Med Hyg 2021; 104:1755-1757. [PMID: 33755582 PMCID: PMC8103489 DOI: 10.4269/ajtmh.20-1448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/11/2021] [Indexed: 11/07/2022] Open
Abstract
Intestinal perforation is one of the most dangerous complications of typhoid fever and demands urgent hospitalization, diagnosis, and surgical management to reduce morbidity and prevent mortality. Here, we report a case of typhoidal intestinal perforation in a 19 year-old young man detected by passive surveillance during a cluster-randomized trial with Vi-tetanus toxoid conjugate vaccine (Typhoid Vaccine Acceleration Consortium: TyVAC) in an urban slum area in Mirpur, Dhaka, Bangladesh. The patient presented with a high-grade fever, lower abdominal pain, and vomiting and was admitted to a healthcare facility. Physical examination and preoperative investigations of the patient suggested a presumptive diagnosis of intestinal perforation, and the patient was transferred to a tertiary-level hospital for surgical management. A positive blood culture, intraoperative findings, and histopathology of an intestinal biopsy confirmed ileal perforation due to typhoid fever. This case report highlights the need for prompt diagnosis and appropriate pre- and postoperative management of patients who appear with the symptoms of typhoidal intestinal perforation. This report further demonstrates the importance of systematic surveillance and proper evaluation to determine the true incidence rate of typhoid fever and intestinal perforation in Bangladesh.
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Affiliation(s)
- Farhana Khanam
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh;,School of Medical Science, Griffith University, Gold Coast, Australia
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Allen G. P. Ross
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - K. Zaman
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - John D. Clemens
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh;,Address correspondence to Firdausi Qadri, Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sharani, Dhaka 1212, Bangladesh. E-mail:
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29
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Carey ME, MacWright WR, Im J, Meiring JE, Gibani MM, Park SE, Longley A, Jeon HJ, Hemlock C, Yu AT, Soura A, Aiemjoy K, Owusu-Dabo E, Terferi M, Islam S, Lunguya O, Jacobs J, Gordon M, Dolecek C, Baker S, Pitzer VE, Yousafzai MT, Tonks S, Clemens JD, Date K, Qadri F, Heyderman RS, Saha SK, Basnyat B, Okeke IN, Qamar FN, Voysey M, Luby S, Kang G, Andrews J, Pollard AJ, John J, Garrett D, Marks F. The Surveillance for Enteric Fever in Asia Project (SEAP), Severe Typhoid Fever Surveillance in Africa (SETA), Surveillance of Enteric Fever in India (SEFI), and Strategic Typhoid Alliance Across Africa and Asia (STRATAA) Population-based Enteric Fever Studies: A Review of Methodological Similarities and Differences. Clin Infect Dis 2021; 71:S102-S110. [PMID: 32725221 PMCID: PMC7388711 DOI: 10.1093/cid/ciaa367] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Building on previous multicountry surveillance studies of typhoid and others salmonelloses such as the Diseases of the Most Impoverished program and the Typhoid Surveillance in Africa Project, several ongoing blood culture surveillance studies are generating important data about incidence, severity, transmission, and clinical features of invasive Salmonella infections in sub-Saharan Africa and South Asia. These studies are also characterizing drug resistance patterns in their respective study sites. Each study answers a different set of research questions and employs slightly different methodologies, and the geographies under surveillance differ in size, population density, physician practices, access to healthcare facilities, and access to microbiologically safe water and improved sanitation. These differences in part reflect the heterogeneity of the epidemiology of invasive salmonellosis globally, and thus enable generation of data that are useful to policymakers in decision-making for the introduction of typhoid conjugate vaccines (TCVs). Moreover, each study is evaluating the large-scale deployment of TCVs, and may ultimately be used to assess post-introduction vaccine impact. The data generated by these studies will also be used to refine global disease burden estimates. It is important to ensure that lessons learned from these studies not only inform vaccination policy, but also are incorporated into sustainable, low-cost, integrated vaccine-preventable disease surveillance systems.
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Affiliation(s)
- Megan E Carey
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Justin Im
- International Vaccine Institute, SNU Research Park, Seoul, Republic of Korea
| | - James E Meiring
- Oxford Vaccine Group, University of Oxford, Oxford, United Kingdom.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Malick M Gibani
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Department of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Se Eun Park
- International Vaccine Institute, SNU Research Park, Seoul, Republic of Korea
| | - Ashley Longley
- Global Immunization Division, Centers for Disease Control Foundation, Atlanta, Georgia, USA
| | - Hyon Jin Jeon
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,International Vaccine Institute, SNU Research Park, Seoul, Republic of Korea
| | - Caitlin Hemlock
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, California, USA
| | - Alexander T Yu
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Abdramane Soura
- Institut Supérieur des Sciences de la Population, University of Ouagadougou, Ouagadougou, Burkina Faso
| | - Kristen Aiemjoy
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Ellis Owusu-Dabo
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Sahidul Islam
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Octavie Lunguya
- Department of Microbiology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of Congo
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Melita Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Christiane Dolecek
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut, USA
| | | | - Susan Tonks
- Oxford Vaccine Group, University of Oxford, Oxford, United Kingdom
| | - John D Clemens
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.,Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California, USA
| | - Kashmira Date
- Global Immunization Division, Centers for Disease Control Foundation, Atlanta, Georgia, USA
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Robert S Heyderman
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Samir K Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Buddha Basnyat
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Iruka N Okeke
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Idaban, Nigeria
| | - Farah N Qamar
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Merryn Voysey
- Oxford Vaccine Group, University of Oxford, Oxford, United Kingdom
| | - Stephen Luby
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | | | - Jason Andrews
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, University of Oxford, Oxford, United Kingdom
| | - Jacob John
- Christian Medical College, Vellore, India
| | - Denise Garrett
- Sabin Vaccine Institute, Washington, District of Columbia, USA
| | - Florian Marks
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,International Vaccine Institute, SNU Research Park, Seoul, Republic of Korea
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30
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Yousafzai MT, Irfan S, Thobani RS, Kazi AM, Hotwani A, Memon AM, Iqbal K, Qazi SH, Saddal NS, Rahman N, Dehraj IF, Hunzai MJ, Mehmood J, Garrett DO, Saha SK, Andrews JR, Luby SP, Qamar FN. Burden of Culture Confirmed Enteric Fever Cases in Karachi, Pakistan: Surveillance For Enteric Fever in Asia Project (SEAP), 2016-2019. Clin Infect Dis 2020; 71:S214-S221. [PMID: 33258931 PMCID: PMC7705869 DOI: 10.1093/cid/ciaa1308] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The Surveillance for Enteric Fever in Asia Project (SEAP) is a multicenter, multicountry study conducted in Pakistan, Nepal, and Bangladesh. The objectives of the study were to characterize disease incidence among patients with enteric fever. We report the burden of enteric fever at selected sites of Karachi, Pakistan. METHODS During September 2016 to September 2019, prospective surveillance was conducted at inpatient, outpatient, surgical departments, and laboratory networks of Aga Khan University Hospital, Kharadar General Hospital, and surgery units of National Institute of Child Health and Jinnah Postgraduate Medical Centre. Socio-demographic, clinical, and laboratory data were obtained from all suspected or confirmed enteric fever cases. RESULTS Overall, 22% (2230/10 094) of patients enrolled were culture-positive for enteric fever. 94% (2093/2230) of isolates were Salmonella Typhi and 6% (137/2230) were S. Paratyphi. 15% of isolates multi-drug resistant (MDR) to first-line antibiotics and 60% were extensively drug-resistant (XDR), resistant to first-line antibiotics, fluoroquinolones and third generation cephalosporin. CONCLUSION Enteric fever cases have increased during the last 3 years with large proportion of drug resistant S. Typhi cases. However, the burden of paratyphoid is still relatively low. Strengthening the existing surveillance system for enteric fever and antimicrobial resistance at the national level is recommended in Pakistan to inform prevention measures. While typhoid vaccination can significantly decrease the burden of typhoid and may also impact antimicrobial resistance, water, sanitation, and hygiene improvement is highly recommended to prevent the spread of enteric fever.
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Affiliation(s)
- Mohammad T Yousafzai
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Seema Irfan
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Rozina S Thobani
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Abdul M Kazi
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Aneeta Hotwani
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Ashraf M Memon
- Clinical Laboratory, Kharadar General Hospital, Karachi, Pakistan
| | - Khalid Iqbal
- Clinical Laboratory, Kharadar General Hospital, Karachi, Pakistan
| | - Saqib H Qazi
- Department of Surgery, Aga Khan University, Karachi, Pakistan
| | | | - Najeeb Rahman
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Irum F Dehraj
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Mohammed J Hunzai
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Junaid Mehmood
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Denise O Garrett
- Applied Epidemiology, Sabin Vaccine Institute, Washington, DC, USA
| | - Samir K Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
| | - Jason R Andrews
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - Stephen P Luby
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - Farah N Qamar
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
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31
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Thindwa D, Farooq YG, Shakya M, Saha N, Tonks S, Anokwa Y, Gordon MA, Hartung C, Meiring JE, Pollard AJ, Heyderman RS. Electronic data capture for large scale typhoid surveillance, household contact tracing, and health utilisation survey: Strategic Typhoid Alliance across Africa and Asia. Wellcome Open Res 2020; 5:66. [PMID: 32934993 PMCID: PMC7471626 DOI: 10.12688/wellcomeopenres.15811.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2020] [Indexed: 11/20/2022] Open
Abstract
Electronic data capture systems (EDCs) have the potential to achieve efficiency and quality in collection of multisite data. We quantify the volume, time, accuracy and costs of an EDC using large-scale census data from the STRATAA consortium, a comprehensive programme assessing population dynamics and epidemiology of typhoid fever in Malawi, Nepal and Bangladesh to inform vaccine and public health interventions. A census form was developed through a structured iterative process and implemented using Open Data Kit Collect running on Android-based tablets. Data were uploaded to Open Data Kit Aggregate, then auto-synced to MySQL-defined database nightly. Data were backed-up daily from three sites centrally, and auto-reported weekly. Pre-census materials' costs were estimated. Demographics of 308,348 individuals from 80,851 households were recorded within an average of 14.7 weeks range (13-16) using 65 fieldworkers. Overall, 21.7 errors (95% confidence interval: 21.4, 22.0) per 10,000 data points were found: 13.0 (95% confidence interval: 12.6, 13.5) and 24.5 (95% confidence interval: 24.1, 24.9) errors on numeric and text fields respectively. These values meet standard quality threshold of 50 errors per 10,000 data points. The EDC's total variable cost was estimated at US$13,791.82 per site. In conclusion, the EDC is robust, allowing for timely and high-volume accurate data collection, and could be adopted in similar epidemiological settings.
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Affiliation(s)
- Deus Thindwa
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, London, UK.,Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Yama G Farooq
- Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford and the National Institute for Health, Oxford, UK
| | - Mila Shakya
- Oxford University Clinical Research Unit-Patan Academy of Health Sciences, Patan, Nepal
| | - Nirod Saha
- International Centre for Diarrhoeal Diseases Research., Dhaka, Bangladesh
| | - Susan Tonks
- Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford and the National Institute for Health, Oxford, UK
| | | | - Melita A Gordon
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | | | - James E Meiring
- Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford and the National Institute for Health, Oxford, UK
| | - Andrew J Pollard
- Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford and the National Institute for Health, Oxford, UK
| | - Robert S Heyderman
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Division of Infection and Immunity, University College London, London, UK
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32
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Iroh Tam PY, Musicha P, Kawaza K, Cornick J, Denis B, Freyne B, Everett D, Dube Q, French N, Feasey N, Heyderman R. Emerging Resistance to Empiric Antimicrobial Regimens for Pediatric Bloodstream Infections in Malawi (1998-2017). Clin Infect Dis 2020; 69:61-68. [PMID: 30277505 PMCID: PMC6579959 DOI: 10.1093/cid/ciy834] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/28/2018] [Indexed: 11/14/2022] Open
Abstract
Background The adequacy of the World Health Organization’s Integrated Management of Childhood Illness (IMCI) antimicrobial guidelines for the treatment of suspected severe bacterial infections is dependent on a low prevalence of antimicrobial resistance (AMR). We describe trends in etiologies and susceptibility patterns of bloodstream infections (BSI) in hospitalized children in Malawi. Methods We determined the change in the population-based incidence of BSI in children admitted to Queen Elizabeth Central Hospital, Blantyre, Malawi (1998–2017). AMR profiles were assessed by the disc diffusion method, and trends over time were evaluated. Results A total 89643 pediatric blood cultures were performed, and 10621 pathogens were included in the analysis. Estimated minimum incidence rates of BSI for those ≤5 years of age fell from a peak of 11.4 per 1000 persons in 2002 to 3.4 per 1000 persons in 2017. Over 2 decades, the resistance of Gram-negative pathogens to all empiric, first-line antimicrobials (ampicillin/penicillin, gentamicin, ceftriaxone) among children ≤5 years increased from 3.4% to 30.2% (P < .001). Among those ≤60 days, AMR to all first-line antimicrobials increased from 7.0% to 67.7% (P < .001). Among children ≤5 years, Klebsiella spp. resistance to all first-line antimicrobial regimens increased from 5.9% to 93.7% (P < .001). Conclusions The incidence of BSI among hospitalized children has decreased substantially over the last 20 years, although gains have been offset by increases in Gram-negative pathogens’ resistance to all empiric first-line antimicrobials. There is an urgent need to address the broader challenge of adapting IMCI guidelines to the local setting in the face of rapidly-expanding AMR in childhood BSI.
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Affiliation(s)
- Pui-Ying Iroh Tam
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Liverpool School of Tropical Medicine, United Kingdom
| | - Patrick Musicha
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Liverpool School of Tropical Medicine, United Kingdom
| | | | - Jenifer Cornick
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Brigitte Denis
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Bridget Freyne
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Dean Everett
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,The Queens Medical Research Institute, University of Edinburgh, United Kingdom
| | - Queen Dube
- University of Malawi College of Medicine, Blantyre
| | - Neil French
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Nicholas Feasey
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,Liverpool School of Tropical Medicine, United Kingdom
| | - Robert Heyderman
- Malawi-Liverpool Wellcome Trust, Institute of Infection and Global Health, University of Liverpool, United Kingdom.,University College London, United Kingdom
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33
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Baker S, Blohmke CJ, Maes M, Johnston PI, Darton TC. The Current Status of Enteric Fever Diagnostics and Implications for Disease Control. Clin Infect Dis 2020; 71:S64-S70. [PMID: 32725220 PMCID: PMC7388712 DOI: 10.1093/cid/ciaa503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Enteric (typhoid) fever remains a problem in low- and middle-income countries that lack the infrastructure to maintain sanitation and where inadequate diagnostic methods have restricted our ability to identify and control the disease more effectively. As we move into a period of potential disease elimination through the introduction of typhoid conjugate vaccine (TCV), we again need to reconsider the role of typhoid diagnostics in how they can aid in facilitating disease control. Recent technological advances, including serology, transcriptomics, and metabolomics, have provided new insights into how we can detect signatures of invasive Salmonella organisms interacting with the host during infection. Many of these new techniques exhibit potential that could be further explored with the aim of creating a new enteric fever diagnostic to work in conjunction with TCV. We need a sustained effort within the enteric fever field to accelerate, validate, and ultimately introduce 1 (or more) of these methods to facilitate the disease control initiative. The window of opportunity is still open, but we need to recognize the need for communication with other research areas and commercial organizations to assist in the progression of these diagnostic approaches. The elimination of enteric fever is now becoming a real possibility, but new diagnostics need to be part of the equation and factored into future calculations for disease control.
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Affiliation(s)
- Stephen Baker
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Mailis Maes
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Peter I Johnston
- Florey Institute for Host-Pathogen Interactions, Department for Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Thomas C Darton
- Florey Institute for Host-Pathogen Interactions, Department for Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
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34
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Abstract
In 1993, the International Task Force on Disease Eradication classified the political will for typhoid eradication as "none." Here we revisit the Task Force's assessment in light of developments in typhoid vaccines and increasing antimicrobial resistance in Salmonella Typhi that have served to increase interest in typhoid elimination. Considering the requisite biological and technical factors for elimination, effective interventions exist for typhoid, and humans are the organism's only known reservoir. Improvements in water supply, sanitation, hygiene, and food safety are critical for robust long-term typhoid control, and the recent Strategic Advisory Group of Experts on Immunization recommendation and World Health Organization prequalification should make typhoid conjugate vaccine more accessible and affordable in low-income countries, which will allow the vaccine to offer a critical bridge to quickly reduce burden. While these developments are encouraging, all current typhoid diagnostics are inadequate, having either poor performance characteristics, limited scalability, or both. No clear solution exists, and this should be viewed as a critical challenge to any elimination effort. Moreover, asymptomatic carriers and limited data and surveillance remain major challenges, and countries considering elimination campaigns will need to develop strategies to identify high-risk populations and to monitor progress over time. Finally, policymakers must be realistic in planning, learn from the planning failures of previous elimination and eradication efforts, and expect unforeseeable shocks and setbacks. In the end, if we assume neither unanticipated breakthroughs in typhoid control nor any chaotic shocks, history suggests that we should expect typhoid elimination to take decades.
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Affiliation(s)
- Jeffrey D Stanaway
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, USA
| | - Phionah L Atuhebwe
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Stephen P Luby
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
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Gibani MM, Voysey M, Jin C, Jones C, Thomaides-Brears H, Jones E, Baker P, Morgan M, Simmons A, Gordon MA, Cerundolo V, Pitzer VE, Angus B, Levine MM, Darton TC, Pollard AJ. The Impact of Vaccination and Prior Exposure on Stool Shedding of Salmonella Typhi and Salmonella Paratyphi in 6 Controlled Human Infection Studies. Clin Infect Dis 2020; 68:1265-1273. [PMID: 30252031 PMCID: PMC6452003 DOI: 10.1093/cid/ciy670] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/07/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Shedding of Salmonella Typhi or Paratyphi in the stool or urine leads to contamination of food or water, which is a prerequisite for transmission of enteric fever. Currently, there are limited data on the effect of vaccination or prior exposure on stool shedding. METHODS Six Salmonella Typhi or Paratyphi human challenge studies were conducted between 2011 and 2017. Participants were either unvaccinated or vaccinated with 1 of 4 vaccines: Vi-polysaccharide (Vi-PS), Vi-tetanus-toxoid conjugate vaccine (Vi-TT), live oral Ty21a vaccine, or an experimental vaccine (M01ZH09). Daily stool cultures were collected for 14 days after challenge. RESULTS There were 4934 stool samples collected from 430 volunteers. Participants who received Vi-PS or Vi-TT shed less than unvaccinated participants (odds ratio [OR], 0.34; 95% confidence interval [CI], 0.15-0.77; P = .010 and OR, 0.41; 95% CI, 0.19-0.91, P = .029 for Vi-PS and Vi-TT, respectively). Higher anti-Vi immunoglobulin G titers were associated with less shedding of S. Typhi (P < .0001). A nonsignificant reduction in shedding was associated with Ty21a vaccine (OR, 0.57; 95% CI, 0.27-1.20; P = .140). Individuals previously exposed to S. Typhi shed less than previously unexposed individuals (OR, 0.30; 95% CI, 0.1-0.8; P = .016). Shedding of S. Typhi was more common than S. Paratyphi. CONCLUSIONS Prior vaccination with Vi vaccines, or natural infection, reduces onward transmission of S. Typhi. Field trials of Vi-TT should be designed to detect indirect protection, reflecting the consequence of reduced stool shedding observed in the human challenge model.
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Affiliation(s)
- Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Nuffield Department of Primary Care Health Sciences, University of Oxford, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | | | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Philip Baker
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Marcus Morgan
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom
| | - Alison Simmons
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom.,Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre.,Institute for Infection and Global Health, University of Liverpool, United Kingdom
| | - Vincenzo Cerundolo
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Brian Angus
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom.,Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
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Theiss-Nyland K, Shakya M, Colin-Jones R, Voysey M, Smith N, Karkey A, Dongol S, Pant D, Farooq YG, Neuzil KM, Shrestha S, Basnyat B, Pollard AJ. Assessing the Impact of a Vi-polysaccharide Conjugate Vaccine in Preventing Typhoid Infections Among Nepalese Children: A Protocol for a Phase III, Randomized Control Trial. Clin Infect Dis 2020; 68:S67-S73. [PMID: 30845329 PMCID: PMC6405280 DOI: 10.1093/cid/ciy1106] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Background Enteric fever is estimated to affect 11–20 million people worldwide each year. Morbidity and mortality from enteric fever primarily occur in lower-income countries, with children under 5 years of age experiencing a significant portion of the burden. Over the last few decades, the control of enteric fever has focused primarily on improved water and sanitation, with the available vaccines unsuitable for children and primarily used by travelers. A new typhoid conjugate vaccine (Vi-TCV), prequalified by the World Health Organization (WHO) and highly immunogenic in children under 5, has the potential to reduce the typhoid burden in endemic countries. Methods This study is a double-blinded, randomized, controlled trial with a 2-year follow-up to assess the protective impact of the Vi-TCV vaccine, compared with a control vaccine, in children from 9 months to 16 years of age. The primary outcome of interest is the reduction in the number of culture-confirmed typhoid cases attributable to Vi-TCV. Approximately 20 000 children living in the Lalitpur district, within the Kathmandu valley, will be enrolled in the study and followed to measure both safety and efficacy data, which will include adverse events, hospitalizations, antibiotic use, and fever frequency. Results Both the intervention and control vaccines are WHO prequalified vaccines, which provide a health benefit to all participants. Children have been chosen to participate because they bear a substantial burden of both typhoid morbidity and mortality in this population. The results of this study will be disseminated through a series of published articles. The findings will also be made available to the participants and the broader community, as well as local stakeholders, within Nepal. Conclusions This is the first large-scale, individually randomized, controlled trial of Vi-TCV in children in an endemic setting, and will provide new data on Vi-TCV field efficacy. With Vi-TCV introduction being considered in high-burden countries, this study will support important policy decisions. Clinical Trials Registration The trial is registered on the ISRCTN registry (for details, see https://doi.org/10.1186/ISRCTN43385161; registry number: ISRCTN 43385161).
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Affiliation(s)
| | - Mila Shakya
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Rachel Colin-Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Nicola Smith
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit-Nepal, Patan Hospital, Kathmandu
| | - Sabina Dongol
- Oxford University Clinical Research Unit-Nepal, Patan Hospital, Kathmandu
| | - Dikshya Pant
- Oxford University Clinical Research Unit-Nepal, Patan Hospital, Kathmandu
| | - Yama G Farooq
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health at the University of Maryland, Baltimore, MD
| | | | - Buddha Basnyat
- Oxford University Clinical Research Unit-Nepal, Patan Hospital, Kathmandu
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
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Meiring JE, Laurens MB, Patel P, Patel P, Misiri T, Simiyu K, Mwakiseghile F, Tracy JK, Masesa C, Liang Y, Henrion M, Rotrosen E, Gmeiner M, Heyderman R, Kotloff K, Gordon MA, Neuzil KM. Typhoid Vaccine Acceleration Consortium Malawi: A Phase III, Randomized, Double-blind, Controlled Trial of the Clinical Efficacy of Typhoid Conjugate Vaccine Among Children in Blantyre, Malawi. Clin Infect Dis 2020; 68:S50-S58. [PMID: 30845320 PMCID: PMC6405268 DOI: 10.1093/cid/ciy1103] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Typhoid fever is an acute infection characterized by prolonged fever following the ingestion and subsequent invasion of Salmonella enterica serovar Typhi (S. Typhi), a human-restricted pathogen. The incidence of typhoid fever has been most reported in children 5-15 years of age, but is increasingly recognized in children younger than 5 years old. There has been a recent expansion of multidrug-resistant typhoid fever globally. Prior typhoid vaccines were not suitable for use in the youngest children in countries with a high burden of disease. This study aims to determine the efficacy of a typhoid conjugate vaccine (TCV) that was recently prequalified by the World Health Organization, by testing it in children 9 months through 12 years of age in Blantyre, Malawi. METHODS In this Phase III, individually randomized, controlled, double-blind trial of the clinical efficacy of TCV, 28 000 children 9 months through 12 years of age will be enrolled and randomized in a 1:1 ratio to receive either Vi-TCV or a meningococcal serogroup A conjugate vaccine. A subset of 600 of these children will be further enrolled in an immunogenicity and reactogenicity sub-study to evaluate the safety profile and immune response elicited by Vi-TCV. Recruiting began in February 2018. RESULTS All children will be under passive surveillance for at least 2 years to determine the primary outcome, which is blood culture-confirmed S. Typhi illness. Children enrolled in the immunogenicity and reactogenicity sub-study will have blood drawn before vaccination and at 2 timepoints after vaccination to measure their immune response to vaccination. They will also be followed actively for adverse events and serious adverse events. CONCLUSIONS The introduction of a single-dose, efficacious typhoid vaccine into countries with high burden of disease or significant antimicrobial resistance could have a dramatic impact, protecting children from infection and reducing antimicrobial usage and associated health inequity in the world's poorest places. This trial, the first of a TCV in Africa, seeks to demonstrate the impact and programmatic use of TCVs within an endemic setting. CLINICAL TRIALS REGISTRATION NCT03299426.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, Oxford University, United Kingdom.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Matthew B Laurens
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Pratiksha Patel
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Priyanka Patel
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Theresa Misiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Kenneth Simiyu
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | | | - J Kathleen Tracy
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Clemens Masesa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Yuanyuan Liang
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Marc Henrion
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Elizabeth Rotrosen
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Markus Gmeiner
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Robert Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Division of Infection and Immunity, University College London, United Kingdom
| | - Karen Kotloff
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
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Theiss-Nyland K, Qadri F, Colin-Jones R, Zaman K, Khanam F, Liu X, Voysey M, Khan A, Hasan N, Ashher F, Farooq YG, Pollard AJ, Clemens JD. Assessing the Impact of a Vi-polysaccharide Conjugate Vaccine in Preventing Typhoid Infection Among Bangladeshi Children: A Protocol for a Phase IIIb Trial. Clin Infect Dis 2020; 68:S74-S82. [PMID: 30845333 PMCID: PMC6405281 DOI: 10.1093/cid/ciy1107] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background Typhoid fever illnesses are responsible for more than 100 000 deaths worldwide each year. In Bangladesh, typhoid fever is endemic, with incidence rates between 292–395 per 100 000 people annually. While considerable effort has been made to improve access to clean water and sanitation services in the country, there is still a significant annual typhoid burden, which particularly affects children. A typhoid conjugate vaccine (Vi-TCV) was recently prequalified by the World Health Organization and recommended for use, and offers the potential to greatly reduce the typhoid burden in Bangladesh. Methods This study is a double-blind, cluster-randomized, controlled trial of Vi-TCV in a geographically defined area in Dhaka, Bangladesh. At least 32 500 children from 9 months to <16 years of age will be vaccinated and followed for 2 years to assess the effectiveness and safety of Vi-TCV in a real-world setting. All cluster residents will also be followed to measure the indirect effect of Vi-TCV in this community. Ethics and Dissemination This protocol has been approved by the International Centre for Diarrhoeal Disease Research, Bangladesh; a University of Oxford research review; and both ethical review committees. Informed written consent and assent will be obtained before enrollment. Vi-TCV has been shown to be safe and effective in previous, smaller-scale studies. The results of this study will be shared through a series of peer-reviewed journal articles. The findings will also be disseminated to the local government, stakeholders within the community, and the population within which the study was conducted. Conclusions This trial is the largest and only cluster-randomized control trial of Vi-TCV ever conducted, and will describe the effectiveness of Vi-TCV in an endemic population. The results of this trial may provide important evidence to support the introduction of TCVs in countries with a high burden of typhoid. Clinical Trials Registration ISRCTN11643110.
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Affiliation(s)
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Rachel Colin-Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - K Zaman
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Xinxue Liu
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Arifuzzaman Khan
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Nazmul Hasan
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Fahim Ashher
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
| | - Yama G Farooq
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - John D Clemens
- International Centre for Diarrhoeal Disease Research-Bangladesh, Dhaka
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Meiring JE, Sambakunsi R, Moyo E, Misiri T, Mwakiseghile F, Patel P, Patel P, Ndaferankhande J, Laurens M, Gooding K, Gordon MA. Community Engagement Before Initiation of Typhoid Conjugate Vaccine Trial in Schools in Two Urban Townships in Blantyre, Malawi: Experience and Lessons. Clin Infect Dis 2020; 68:S146-S153. [PMID: 30845322 PMCID: PMC6405274 DOI: 10.1093/cid/ciy1110] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND To determine the efficacy of a new typhoid conjugate vaccine in an endemic setting in sub-Saharan Africa, the Typhoid Vaccine Acceleration Consortium is conducting a phase-3 randomized controlled trial in Blantyre, Malawi. This article describes community and stakeholder engagement activities before and during the trial, challenges, and lessons learned. METHODS In October 2017, Malawi-Liverpool Wellcome Trust (MLW) organized a wide range of community engagement activities, including meetings with Ministry of Health and Education officials at the district and facility level, local community leadership, and parent teacher association groups. We engaged media outlets to include local and international television, radio, and print media. Community members were informed directly through a study jingle played via loudspeaker from a van and by community-based activities.To review engagement activity effectiveness: The MLW team met to discuss progress and challenges; and a focus group discussion (FGD), consisting of trial staff, sought feedback from the community on each engagement modality. RESULTS The school-based vaccine campaign increased community participation exceeding recruitment targets to date (on average, >200 children/day). CONCLUSIONS The FGD concluded that the van and local activities improved awareness and turnout for the trial, but prior engagement with local government and community leadership is an essential mechanism to provide details of the study, answer questions, communicate the value of the study, and address safety concerns. Effective community engagement is essential in a large intervention trial. Multiple channels of communication are required to reach the community and deliver information needed for participation and provide opportunity for dialogue with the trial team.
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Affiliation(s)
- James E Meiring
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Oxford Vaccine Group, Department of Paediatrics, Oxford University, United Kingdom
| | - Rodrick Sambakunsi
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Elvis Moyo
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Theresa Misiri
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Pratiksha Patel
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Priyanka Patel
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - John Ndaferankhande
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Matthew Laurens
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Kate Gooding
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Melita A Gordon
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
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Khanam F, Rajib NH, Tonks S, Khalequzzaman M, Pollard AJ, Clemens JD, Qadri F, And The Strataa Study Team. Case Report: Salmonella Enterica Serovar Paratyphi B Infection in a Febrile Ill Child during Enhanced Passive Surveillance in an Urban Slum in Mirpur, Dhaka. Am J Trop Med Hyg 2020; 103:231-233. [PMID: 32458786 PMCID: PMC7356450 DOI: 10.4269/ajtmh.19-0958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Paratyphoid fever is one of the major causes of morbidity of febrile illnesses in endemic regions. We report a case of high-grade fever in an infant who was positive for Salmonella enterica serovar Paratyphi B (S. Paratyphi B) both in blood and stool cultures. The baby was enrolled in the passive surveillance of multicenter, multicomponent epidemiological study of enteric fever (Strategic Typhoid alliance across Africa and Asia; STRATAA) conducted in a population of 110,000 residents over 2 years in an urban slum, Dhaka, Bangladesh. This is the only patient who was positive for S. Paratyphi B in blood and stool among more than 6,000 febrile ill patients enrolled in the passive surveillance. The report shows the significance of surveillance to identify changes in the epidemiology of enteric fever.
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Affiliation(s)
- Farhana Khanam
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Nazmul Hasan Rajib
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Susan Tonks
- Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Md Khalequzzaman
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Andrew J Pollard
- Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - John D Clemens
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
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Thindwa D, Farooq YG, Shakya M, Saha N, Tonks S, Anokwa Y, Gordon MA, Hartung C, Meiring JE, Pollard AJ, Heyderman RS. Electronic data capture for large scale typhoid surveillance, household contact tracing, and health utilisation survey: Strategic Typhoid Alliance across Africa and Asia. Wellcome Open Res 2020; 5:66. [DOI: 10.12688/wellcomeopenres.15811.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2020] [Indexed: 12/25/2022] Open
Abstract
Electronic data capture systems (EDCs) have the potential to achieve efficiency and quality in collection of multisite data. We quantify the volume, time, accuracy and costs of an EDC using large-scale census data from the STRATAA consortium, a comprehensive programme assessing population dynamics and epidemiology of typhoid fever in Malawi, Nepal and Bangladesh to inform vaccine and public health interventions. A census form was developed through a structured iterative process and implemented using Open Data Kit Collect running on Android-based tablets. Data were uploaded to Open Data Kit Aggregate, then auto-synced to MySQL-defined database nightly. Data were backed-up daily from three sites centrally, and auto-reported weekly. Pre-census materials’ costs were estimated. Demographics of 308,348 individuals from 80,851 households were recorded within an average of 14.7 weeks range (13-16) using 65 fieldworkers. Overall, 21.7 errors (95% confidence interval: 21.4, 22.0) per 10,000 data points were found: 13.0 (95% confidence interval: 12.6, 13.5) and 24.5 (95% confidence interval: 24.1, 24.9) errors on numeric and text fields respectively. These values meet standard quality threshold of 50 errors per 10,000 data points. The EDC’s total variable cost was estimated at US$13,791.82 per site. In conclusion, the EDC is robust, allowing for timely and high-volume accurate data collection, and could be adopted in similar epidemiological settings.
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Neuzil KM, Pollard AJ, Marfin AA. Introduction of Typhoid Conjugate Vaccines in Africa and Asia. Clin Infect Dis 2020; 68:S27-S30. [PMID: 30767005 PMCID: PMC6376078 DOI: 10.1093/cid/ciy878] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Typhoid fever continues to be a major public health concern, particularly in many low- and middle-income countries. The current threats of increasing antimicrobial resistance, urbanization, and climate change elevate the urgency for better prevention and control efforts for typhoid fever. In 2017, the results of ground-breaking research on typhoid conjugate vaccines (TCVs), the World Health Organization prequalification of a TCV, and global policy and financing decisions have set the stage for the introduction of TCVs into routine immunization programs in endemic countries. Country-level decision-making and program planning are critical for local uptake and sustainability.
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Affiliation(s)
- Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
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43
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Thindwa D, Chipeta MG, Henrion MYR, Gordon MA. Distinct climate influences on the risk of typhoid compared to invasive non-typhoid Salmonella disease in Blantyre, Malawi. Sci Rep 2019; 9:20310. [PMID: 31889080 PMCID: PMC6937328 DOI: 10.1038/s41598-019-56688-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/02/2019] [Indexed: 12/04/2022] Open
Abstract
Invasive Salmonella diseases, both typhoid and invasive non-typhoidal Salmonella (iNTS), are seasonal bloodstream infections causing important morbidity and mortality globally in Africa. The reservoirs and transmission of both are not fully understood. We hypothesised that differences in the time-lagged relationships of rainfall or temperature with typhoid and iNTS incidence might infer differences in epidemiology. We assessed the dynamics of invasive Salmonella incidence over a 16-year period of surveillance, quantifying incidence peaks, seasonal variations, and nonlinear effects of rainfall and temperature exposures on the relative risks of typhoid and iNTS, using monthly lags. An increased relative risk of iNTS incidence was short-lasting but immediate after the onset of the rains, whereas that of typhoid was long-lasting but with a two months delayed start, implying a possible difference in transmission. The relative-risk function of temperature for typhoid was bimodal, with higher risk at both lower (with a 1 month lag) and higher (with a ≥4 months lag) temperatures, possibly reflecting the known patterns of short and long cycle typhoid transmission. In contrast, the relative-risk of iNTS was only increased at lower temperatures, suggesting distinct transmission mechanisms. Environmental and sanitation control strategies may be different for iNTS compared to typhoid disease.
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Affiliation(s)
- Deus Thindwa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| | - Michael G Chipeta
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Nuffield Department of Medicine, Big Data Institute, Oxford University, Oxford, United Kingdom
- Malawi College of Medicine, University of Malawi, Blantyre, Malawi
| | - Marc Y R Henrion
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- Malawi College of Medicine, University of Malawi, Blantyre, Malawi
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44
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Carey ME, Steele AD. The Severe Typhoid Fever in Africa Program Highlights the Need for Broad Deployment of Typhoid Conjugate Vaccines. Clin Infect Dis 2019; 69:S413-S416. [PMID: 31665775 PMCID: PMC6821154 DOI: 10.1093/cid/ciz637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Typhoid Surveillance in Africa Program (TSAP) and the Severe Typhoid Fever in Africa (SETA) program have refined our understanding of age and geographic distribution of typhoid fever and other invasive salmonelloses in Africa and will help inform future typhoid control strategies, namely, introduction of typhoid conjugate vaccines.
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Affiliation(s)
- Megan E Carey
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - A Duncan Steele
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
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Carey ME, Diaz ZI, Broadstock M, Bailey R, Bentsi-Enchill AD, Larson HJ. Toward Control? The Prospects and Challenges of Typhoid Conjugate Vaccine Introduction. Clin Infect Dis 2019; 69:S408-S411. [PMID: 31612940 PMCID: PMC6792119 DOI: 10.1093/cid/ciz483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
With a newly World Health Organization (WHO)-prequalified typhoid conjugate vaccine (TCV), Gavi funding for eligible countries, and a WHO policy recommendation for TCV use, now is the time for countries to introduce TCVs as part of an integrated typhoid control program, particularly in light of the increasing burden of antimicrobial resistance. Continued vaccine development efforts will lead to secure supply of low-cost vaccines, and ongoing vaccine studies will provide critical vaccine performance data and inform optimal deployment strategies, in both routine use and in outbreak settings. TCV programs should include thoughtful communication planning and community engagement to counter vaccine hesitancy.
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Affiliation(s)
- Megan E Carey
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Zoey I Diaz
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
| | | | - Roderick Bailey
- Wellcome Centre for Ethics and Humanities, University of Oxford, United Kingdom
| | - Adwoa D Bentsi-Enchill
- Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland
| | - Heidi J Larson
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, United Kingdom
- Department of Health Metrics and Evaluation, University of Washington, Seattle
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Meiring JE, Giubilini A, Savulescu J, Pitzer VE, Pollard AJ. Generating the Evidence for Typhoid Vaccine Introduction: Considerations for Global Disease Burden Estimates and Vaccine Testing Through Human Challenge. Clin Infect Dis 2019; 69:S402-S407. [PMID: 31612941 PMCID: PMC6792111 DOI: 10.1093/cid/ciz630] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Typhoid fever has had a major impact on human populations, with the causative pathogen Salmonella enterica serovar Typhi implicated in many outbreaks through history. The current burden of disease is estimated at 11-18 million infections annually, with the majority of infections located in Africa and South Asia. Data that have been used to estimate burden are limited to a small number of blood-culture surveillance studies, largely from densely populated urban centers. Extrapolating these data to estimate disease burden within and across countries highlights the lack of precision in global figures. A number of approaches have been developed, characterizing different geographical areas by water-based risk factors for typhoid infection or broader measures of health and development to more accurately extrapolate incidence. Recognition of the substantial disease burden is essential for policy-makers considering vaccine introduction. Typhoid vaccines have been in development for >100 years. The Vi polysaccharide (ViPS) and Ty21a vaccines have had a World Health Organization (WHO) recommendation for programmatic use in countries with high burden for 10 years, with 1 ViPS vaccine also having WHO prequalification. Despite this, uptake and introduction of these vaccines has been minimal. The development of a controlled human infection model (CHIM) enabled the accelerated testing of the newly WHO-prequalified ViPS-tetanus toxoid protein conjugate vaccine, providing efficacy estimates for the vaccine, prior to larger field trials. There is an urgency to the global control of enteric fever due to the escalating problem of antimicrobial resistance. With more accurate burden of disease estimates and a vaccine showing efficacy in CHIM, that control is now a possibility.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
| | - Alberto Giubilini
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Julian Savulescu
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
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Bentsi-Enchill AD, Pollard AJ. A Turning Point in Typhoid Control. J Infect Dis 2019; 218:S185-S187. [PMID: 30189009 PMCID: PMC6226784 DOI: 10.1093/infdis/jiy417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/29/2018] [Indexed: 12/03/2022] Open
Affiliation(s)
- Adwoa D Bentsi-Enchill
- Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom.,National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
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Saha S, Uddin MJ, Islam M, Das RC, Garrett D, Saha SK. Enteric Fever Cases in the Two Largest Pediatric Hospitals of Bangladesh: 2013-2014. J Infect Dis 2019; 218:S195-S200. [PMID: 30277511 PMCID: PMC6226791 DOI: 10.1093/infdis/jiy521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background Enteric fever predominantly affects children in low- and middle-income countries. This study examines the burden of enteric fever at the 2 pediatric hospitals in Dhaka, Bangladesh and assesses their capacity for inclusion in a prospective cohort study to support enteric fever prevention and control. Methods A descriptive study of enteric fever was conducted among children admitted in 2013–2014 to inpatient departments of Dhaka Shishu and Shishu Shashthya Foundation Hospitals, sentinel hospitals of the World Health Organization-supported Invasive Bacterial Vaccine Preventable Disease surveillance platform. Results Of 15917 children with blood specimens received by laboratories, 2.8% (443 of 15917) were culture positive for significant bacterial growth. Sixty-three percent (279 of 443) of these isolates were confirmed as the cases of enteric fever (241 Salmonella Typhi and 38 Salmonella Paratyphi A). In addition, 1591 children had suspected enteric fever. Overall, 3.6% (1870 of 51923) were laboratory confirmed or suspected enteric fever cases (55% male, median age 2 years, 86% from Dhaka district, median hospital stay 5 days). Conclusions The burden of enteric fever among inpatients at 2 pediatric hospitals in Dhaka, Bangladesh is substantial. Therefore, inclusion of these hospitals in a prospective cohort study will be useful for the generation of credible disease burden estimates of enteric fever in Bangladesh.
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Affiliation(s)
- Shampa Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
| | - Mohammad J Uddin
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
| | - Maksuda Islam
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
| | - Rajib C Das
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
| | | | - Samir Kumar Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh.,Bangladesh Institute of Child Health, Dhaka Shishu (Children) Hospital, Bangladesh
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Abstract
Purpose of review Enteric fever remains a major global-health concern, estimated to be responsible for between 11.9 and 26.9 million cases annually. Long-term prevention of enteric fever will require improved access to safe drinking water combined with investment in sanitation and hygiene interventions. In the short-to-medium term, new control strategies for typhoid fever have arrived in the form of typhoid Vi-conjugate vaccines (TCVs), offering hope that disease control can be achieved in the near future. Recent findings The diagnosis of enteric fever is complicated by its nonspecific clinical presentation, coupled with the low sensitivity of commonly used diagnostics. Investment in diagnostics has the potential to improve management, to refine estimates of disease burden and to facilitate vaccine impact studies. A new generation of reliable, diagnostic tests is needed that are simultaneously accessible, cost-effective, sensitive, and specific. The emergence and global dissemination of multidrug-resistant, fluoroquinolone-resistant, and extensively drug-resistant (XDR) strains of Salmonella Typhi emphasizes the importance of continued surveillance and appropriate antibiotic stewardship, integrated into a global strategy to address antimicrobial resistance (AMR). Current empirical treatment guidelines are out of date and should be updated to respond to local trends in AMR, so as to guide treatment choices in the absence of robust diagnostics and laboratory facilities. In September 2017, the WHO Strategic Advisory Group of Experts (SAGE) immunization recommended the programmatic use of TCVs in high burden countries. Ongoing and future studies should aim to study the impact of these vaccines in a diverse range of setting and to support the deployment of TCVs in high-burden countries. Summary The advent of new generation TCVs offers us a practical and affordable public-health tool that – for the first time – can be integrated into routine childhood immunization programmes. In this review, we advocate for the deployment of TCVs in line with WHO recommendations, to improve child health and limit the spread of antibiotic-resistant S. Typhi.
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Bilcke J, Antillón M, Pieters Z, Kuylen E, Abboud L, Neuzil KM, Pollard AJ, Paltiel AD, Pitzer VE. Cost-effectiveness of routine and campaign use of typhoid Vi-conjugate vaccine in Gavi-eligible countries: a modelling study. THE LANCET. INFECTIOUS DISEASES 2019; 19:728-739. [PMID: 31130329 PMCID: PMC6595249 DOI: 10.1016/s1473-3099(18)30804-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Typhoid fever is a major cause of morbidity and mortality in low-income and middle-income countries. In 2017, WHO recommended the programmatic use of typhoid Vi-conjugate vaccine (TCV) in endemic settings, and Gavi, The Vaccine Alliance, has pledged support for vaccine introduction in these countries. Country-level health economic evaluations are now needed to inform decision-making. METHODS In this modelling study, we compared four strategies: no vaccination, routine immunisation at 9 months, and routine immunisation at 9 months with catch-up campaigns to either age 5 years or 15 years. For each of the 54 countries eligible for Gavi support, output from an age-structured transmission-dynamic model was combined with country-specific treatment and vaccine-related costs, treatment outcomes, and disability weights to estimate the reduction in typhoid burden, identify the strategy that maximised average net benefit (ie, the optimal strategy) across a range of country-specific willingness-to-pay (WTP) values, estimate and investigate the uncertainties surrounding our findings, and identify the epidemiological conditions under which vaccination is optimal. FINDINGS The optimal strategy was either no vaccination or TCV immunisation including a catch-up campaign. Routine vaccination with a catch-up campaign to 15 years of age was optimal in 38 countries, assuming a WTP value of at least US$200 per disability-adjusted life-year (DALY) averted, or assuming a WTP value of at least 25% of each country's gross domestic product (GDP) per capita per DALY averted, at a vaccine price of $1·50 per dose (but excluding Gavi's contribution according to each country's transition phase). This vaccination strategy was also optimal in 48 countries assuming a WTP of at least $500 per DALY averted, in 51 with assumed WTP values of at least $1000, in 47 countries assuming a WTP value of at least 50% of GDP per capita per DALY averted, and in 49 assuming a minimum of 100%. Vaccination was likely to be cost-effective in countries with 300 or more typhoid cases per 100 000 person-years. Uncertainty about the probability of hospital admission (and typhoid incidence and mortality) had the greatest influence on the optimal strategy. INTERPRETATION Countries should establish their own WTP threshold and consider routine TCV introduction, including a catch-up campaign when vaccination is optimal on the basis of this threshold. Obtaining improved estimates of the probability of hospital admission would be valuable whenever the optimal strategy is uncertain. FUNDING Bill & Melinda Gates Foundation, Research Foundation-Flanders, and the Belgian-American Education Foundation.
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Affiliation(s)
- Joke Bilcke
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
| | - Marina Antillón
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Zoë Pieters
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium; Center for Statistics, I-Biostat, Hasselt University, Diepenbeek, Belgium
| | - Elise Kuylen
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Linda Abboud
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - A David Paltiel
- Department of Health Policy and Management, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA.
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