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Batool R, Qamar ZH, Salam RA, Yousafzai MT, Ashorn P, Qamar FN. Efficacy of typhoid vaccines against culture-confirmed Salmonella Typhi in typhoid endemic countries: a systematic review and meta-analysis. Lancet Glob Health 2024; 12:e589-e598. [PMID: 38485426 DOI: 10.1016/s2214-109x(23)00606-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 03/19/2024]
Abstract
BACKGROUND Typhoid is a serious public health threat in many low-income and middle-income countries. Several vaccines for typhoid have been recommended by WHO for typhoid prevention in endemic countries. This study aimed to review the efficacy of typhoid vaccines against culture-confirmed Salmonella enterica serovar Typhi. METHODS We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for studies published in English between Jan 1, 1986 and Nov 2, 2023. We included randomised controlled trials (RCTs) comparing typhoid vaccines with a placebo or another vaccine. This meta-analysis evaluated the efficacy and safety of several typhoid vaccines, including live attenuated oral Ty21a vaccine, Vi capsular polysaccharide (Vi-PS), Vi polysaccharide conjugated to recombinant Pseudomonas aeruginosa exotoxin A vaccine (Vi-rEPA), and Vi-tetanus toxoid conjugate vaccine (TCV). The certainty of evidence for key outcomes was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations methodology. The outcome of interest was typhoid fever confirmed by the isolation of Salmonella enterica serovar Typhi in blood and adverse events following immunisation. This study is registered with PROSPERO (CRD42021241043). FINDINGS We included 14 RCTs assessing four different vaccines (Ty21a: four trials; Vi-PS: five trials; Vi-rEPA: one trial; TCV: four trials) involving 585 253 participants. All trials were conducted in typhoid endemic countries and the age of participants ranged from 6 months to 50 years. The pooled efficacy against typhoid fever was 45% (95% CI 33-55%; four trials; 247 649 participants; I2 59%; moderate certainty) for Ty21a and 58% (44-69%; five trials; 214 456 participants; I2 34%; moderate certainty) for polysaccharide Vi-PS. The cumulative efficacy of two doses of Vi-rEPA vaccine at 2 years was 91% (88-96%; one trial; 12 008 participants; moderate certainty). The pooled efficacy of a single shot of TCV at 2 years post-immunisation was 83% (77-87%; four trials; 111 130 participants; I2 0%; moderate certainty). All vaccines were safe, with no serious adverse effects reported in the trials. INTERPRETATION The existing data from included trials provide promising results regarding the efficacy and safety of the four recommended typhoid vaccines. TCV and Vi-rEPA were found to have the highest efficacy at 2 years post-immunisation. However, follow-up data for Vi-rEPA are scarce and only TCV is pre-qualified by WHO. Therefore, roll-out of TCV into routine immunisation programmes in typhoid endemic settings is highly recommended. FUNDING There was no funding source for this study.
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Affiliation(s)
- Rabab Batool
- Department of Epidemiology and Biostatistics, Aga Khan University Hospital, Karachi, Pakistan; Department of Pediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan; Centre for Child, Adolescent, and Maternal Health Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Zoya Haq Qamar
- Liaquat National Hospital and Medical College, Karachi, Pakistan
| | | | - Mohammad Tahir Yousafzai
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan; The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Per Ashorn
- Centre for Child, Adolescent, and Maternal Health Research, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan.
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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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3
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Haque S, Sengupta S, Khan A, Mukhopadhyay AK, Bhan MK, Kumar R, Jailkhani B. Immune response of S. Typhi-derived Vi polysaccharide and outer membrane protein a conjugate in mice. Pediatr Neonatol 2023; 64:518-527. [PMID: 36868948 DOI: 10.1016/j.pedneo.2022.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/06/2022] [Accepted: 12/20/2022] [Indexed: 02/19/2023] Open
Abstract
Typhoid fever is a serious concern precisely in developing nations. Still investigators are exploring a better conjugate partner for Vi-polysaccharide to develop a more effective vaccine for typhoid fever. Here, we cloned and expressed S. Typhi outer membrane protein A (OmpA). The conjugation of Vi-polysaccharide with OmpA was carried out by the carbodiimide (EDAC) method employing ADH as a linker. Total Ig and IgG generated against OmpA, and Vi polysaccharide was quantified by ELISA. Vi polysaccharide alone induced very low levels of Vi polysaccharide antibody. Vi-OmpA conjugate (Vi-conjugate) elicited a robust immune response compared to Vi polysaccharide alone and showed booster response. Further, IgG was only evoked by Vi-OmpA conjugate, not with Vi polysaccharide alone. OmpA antibody induction in both the Vi-OmpA conjugate and OmpA were similar level. Taken together, we show that OmpA as a carrier protein conjugated to Vi polysaccharide is immunogenic. We predict OmpA antibodies will contribute protection along with antibodies generated by Vi-polysaccharide. Past and current literature supports that OmpA is highly conserved protein not only among Salmonellae but entire Enterobacteriacea family with 96-100% identity.
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Affiliation(s)
- Shabirul Haque
- Department of Autoimmune Diseases, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA; Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
| | - Sanjukta Sengupta
- Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Azhar Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, India
| | - Asok Kumar Mukhopadhyay
- Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Maharaj Kishan Bhan
- Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Ramesh Kumar
- Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Bansilal Jailkhani
- Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
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Kumar S, Ghosh RS, Iyer H, Ray A, Vannice K, MacLennan C, Shewchuk T, Steele D. Typhoid in India: An Age-old Problem With an Existing Solution. J Infect Dis 2021; 224:S469-S474. [PMID: 35238361 PMCID: PMC8892544 DOI: 10.1093/infdis/jiab441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Enteric fever continues to impact millions of people who lack adequate access to clean water and sanitation. The typhoid and paratyphoid fever burden in South Asia is broadly acknowledged, but current estimates of incidence, severity, and cost of illness from India are lacking. This supplement addresses this gap in our knowledge, presenting findings from two years of surveillance, conducted at multiple sites between October 2017 and February 2020, in the Surveillance for Enteric Fever in India (SEFI) network. Results provide contemporaneous evidence of high disease burden and cost of illness-the latter borne largely by patients in the absence of universal healthcare coverage in India. Against a backdrop of immediate priorities in the COVID-19 pandemic, these data are a reminder that typhoid, though often forgotten, remains a public health problem in India. Typhoid conjugate vaccines, produced by multiple Indian manufacturers, and recommended for use in high burden settings, ensure that the tools to tackle typhoid are an immediately available solution to this public health problem.
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Affiliation(s)
- Supriya Kumar
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington,USA
| | - Raj Shankar Ghosh
- India Country Office, Bill & Melinda Gates Foundation, New Delhi, India
| | - Harish Iyer
- India Country Office, Bill & Melinda Gates Foundation, New Delhi, India
| | - Arindam Ray
- India Country Office, Bill & Melinda Gates Foundation, New Delhi, India
| | - Kirsten Vannice
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington,USA
| | - Calman MacLennan
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington,USA
| | - Tanya Shewchuk
- Global Delivery Program, Bill & Melinda Gates Foundation, Seattle, Washington,USA
| | - Duncan Steele
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington,USA
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Haque S, Swami P, Khan A. S. Typhi derived vaccines and a proposal for outer membrane vesicles (OMVs) as potential vaccine for typhoid fever. Microb Pathog 2021; 158:105082. [PMID: 34265371 DOI: 10.1016/j.micpath.2021.105082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 12/22/2022]
Abstract
Typhoid fever is a serious systemic infection caused by Salmonella Typhi (S. Typhi), spread by the feco-oral route and closely associated with poor food hygiene and inadequate sanitation. Nearly 93% of S. Typhi strains have acquired antibiotic resistance against most antibiotics. Vaccination is the only promising way to prevent typhoid fever. This review covers the nature and composition of S. Typhi, pathogenecity and mode of infection, epidemiology, and nature of drug resistance. Several components (Vi-polysaccharides, O-antigens, flagellar antigens, full length OMPs, and short peptides from OMPs) of S. Typhi have been utilized for vaccine design for protection against typhoid fever. Vaccine delivery systems also contribute to efficacy of the vaccines. In this study, we propose to develop S. Typhi derived OMVs as vaccine for protection against typhoid fevers.
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Affiliation(s)
- Shabirul Haque
- Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
| | - Pooja Swami
- Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
| | - Azhar Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal, Pradesh, India.
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Anti-glycan antibodies: roles in human disease. Biochem J 2021; 478:1485-1509. [PMID: 33881487 DOI: 10.1042/bcj20200610] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 02/07/2023]
Abstract
Carbohydrate-binding antibodies play diverse and critical roles in human health. Endogenous carbohydrate-binding antibodies that recognize bacterial, fungal, and other microbial carbohydrates prevent systemic infections and help maintain microbiome homeostasis. Anti-glycan antibodies can have both beneficial and detrimental effects. For example, alloantibodies to ABO blood group carbohydrates can help reduce the spread of some infectious diseases, but they also impose limitations for blood transfusions. Antibodies that recognize self-glycans can contribute to autoimmune diseases, such as Guillain-Barre syndrome. In addition to endogenous antibodies that arise through natural processes, a variety of vaccines induce anti-glycan antibodies as a primary mechanism of protection. Some examples of approved carbohydrate-based vaccines that have had a major impact on human health are against pneumococcus, Haemophilus influeanza type b, and Neisseria meningitidis. Monoclonal antibodies specifically targeting pathogen associated or tumor associated carbohydrate antigens (TACAs) are used clinically for both diagnostic and therapeutic purposes. This review aims to highlight some of the well-studied and critically important applications of anti-carbohydrate antibodies.
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Ghaderi E, Zahraei SM, Moradi G, Goodarzi E, Norouzinejad A, Mohsenpour B, Naemi H, Khazaei Z. Geographical distribution of Typhoid using Geographic Information System (GIS) during 2009-2014 in Iran. Med J Islam Repub Iran 2021; 35:35. [PMID: 34211937 PMCID: PMC8236083 DOI: 10.47176/mjiri.35.35] [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: 02/14/2020] [Indexed: 11/09/2022] Open
Abstract
Background: Salmonella induced infections remain one of the most important health problems worldwide. The purpose of this study is to investigate the incidence and geographical distribution of typhoid using GIS and to predict its incidence in Iran in 2021.
Methods: This study is a descriptive analytical study. Information on pertussis was obtained from the Center for Communicable Diseases Control during 2009-2015. In the next step, ArcGIS 9.3 was used to prepare geographic maps of the disease incidence and frequency Therefore, using the Raster Calculator tool, the disease prediction map was drawn.
Results: The results showed that the highest incidence of typhoid during 2009-2014 was in Kermanshah, Lorestan, Hamadan, Kurdistan, and Ilam provinces. The incidence of typhoid in Iran increased during 2009-2010. The annual incidence of typhoid decreased from 0.85 per 100,000 in 2010 to 0.5 in 2014. Based on the modeling results for Iran, Kermanshah, Lorestan, Kurdistan, Ilam and Hamadan provinces with 92.17%, 46.56%, 31.74%, 25.62% and 22.96% of their areas (Km2) are at high risk for typhoid in the coming years, respectively.
Conclusion: Considering that the provinces of Kermanshah, Lorestan, Kurdistan, Ilam, and Hamadan are at risk of typhoid incidence in the coming years in Iran, and given that salmonella infections have a direct relationship with the individual’s health status and individual’s environmental health and socioeconomic status, improving the health status and disease control in carriers as well as improving the socio-economic status of the population living in these areas can prevent the disease in the years to come.
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Affiliation(s)
- Ebrahim Ghaderi
- Zoonoses Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Seyed Mohsen Zahraei
- Center for Communicable Diseases Control, Ministry of Health and Medical Education, Tehran, Iran
| | - Ghobad Moradi
- Social Determinants of Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Elham Goodarzi
- Social Determinants of Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Abbas Norouzinejad
- Deputy for Administrative Affairs The Center for Communicable Disease Control, Ministry of Health and Medical Education, Tehran, Iran
| | - Behzad Mohsenpour
- Department of Infectious Disease, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Hasan Naemi
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Zaher Khazaei
- Department of Public Health,School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
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9
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Vashishtha VM, Kalra A. The need & the issues related to new-generation typhoid conjugate vaccines in India. Indian J Med Res 2021; 151:22-34. [PMID: 32134011 PMCID: PMC7055164 DOI: 10.4103/ijmr.ijmr_1890_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The low- and middle-income countries bear the highest burden of typhoid fever in the world. India, along with other South Asian countries, has a significant incidence of typhoid fever among young children though there is a paucity of published data on community burden. In spite of the availability of Vi-polysaccharide (Vi-PS) and conjugated Vi-PS vaccines, these are not adequately utilized in India and in the neighbouring countries. To address many shortcomings of the unconjugated Vi-PS vaccines, typhoid conjugate vaccines (TCVs) are developed by conjugating Vi-PS with different carrier proteins. Three such vaccines using tetanus toxoid as a carrier protein are already licensed in India. Several other Vi-PS conjugates are currently in various stages of development. The current review provides an update on the existing and upcoming new TCVs along with a detailed discussion on the various issues involved with their clinical use and limitations.
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Affiliation(s)
| | - Ajay Kalra
- Department of Pediatrics, Sarojini Naidu Medical College, Agra, Uttar Pradesh, India
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Masuet-Aumatell C, Atouguia J. Typhoid fever infection - Antibiotic resistance and vaccination strategies: A narrative review. Travel Med Infect Dis 2020; 40:101946. [PMID: 33301931 DOI: 10.1016/j.tmaid.2020.101946] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
Typhoid fever is a bacterial infection caused by the Gram-negative bacterium Salmonella enterica subspecies enterica serovar Typhi (S. Typhi), prevalent in many low- and middle-income countries. In high-income territories, typhoid fever is predominantly travel-related, consequent to travel in typhoid-endemic regions; however, data show that the level of typhoid vaccination in travellers is low. Successful management of typhoid fever using antibiotics is becoming increasingly difficult due to drug resistance; emerging resistance has spread geographically due to factors such as increasing travel connectivity, affecting those in endemic regions and travellers alike. This review provides an overview of: the epidemiology and diagnosis of typhoid fever; the emergence of drug-resistant typhoid strains in the endemic setting; drug resistance observed in travellers; vaccines currently available to prevent typhoid fever; vaccine recommendations for people living in typhoid-endemic regions; strategies for the introduction of typhoid vaccines and stakeholders in vaccination programmes; and travel recommendations for a selection of destinations with a medium or high incidence of typhoid fever.
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Affiliation(s)
- Cristina Masuet-Aumatell
- Preventive Medicine Department, Bellvitge Biomedical Research Institute (IDIBELL), University Hospital of Bellvitge, Faculty of Medicine, University of Barcelona, Feixa Llarga s/n, L'Hospitalet de Llobregat, 08907, Barcelona, Catalonia, Spain.
| | - Jorge Atouguia
- Instituto Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junquiera, 100, Lisbon, Portugal.
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Tamrakar D, Vaidya K, Yu AT, Aiemjoy K, Naga SR, Cao Y, Bern C, Shrestha R, Karmacharya BM, Pradhan S, Qamar FN, Saha S, Date K, Longley AT, Hemlock C, Luby S, Garrett DO, Bogoch II, Andrews JR. Spatial Heterogeneity of Enteric Fever in 2 Diverse Communities in Nepal. Clin Infect Dis 2020; 71:S205-S213. [PMID: 33258932 PMCID: PMC7705881 DOI: 10.1093/cid/ciaa1319] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Typhoid fever is endemic in the urban Kathmandu Valley of Nepal; however, there have been no population-based studies of typhoid outside of this community in the past 3 decades. Whether typhoid immunization should be prioritized in periurban and rural communities has been unclear. METHODS We performed population-based surveillance for enteric fever in 1 urban catchment (Kathmandu) and 1 periurban and rural catchment (Kavrepalanchok) as part of the Surveillance for Enteric Fever in Asia Project (SEAP). We recruited individuals presenting to outpatient and emergency departments at 2 study hospitals with suspected enteric fever and performed blood cultures. Additionally, we conducted a household survey in each catchment area to characterize care seeking for febrile illness. We evaluated spatial heterogeneity in febrile illness, care seeking, and enteric fever incidence. RESULTS Between September 2016 and September 2019, we enrolled 5736 participants with suspected enteric fever at 2 study hospitals. Among these, 304 (5.3%) were culture positive for Salmonella Typhi (249 [81.9%]) or Paratyphi A (55 [18.1%]). Adjusted typhoid incidence in Kathmandu was 484 per 100 000 person-years and in Kavrepalanchok was 615 per 100 000 person-years. While all geographic areas for which estimates could be made had incidence >200 per 100 000 person-years, we observed spatial heterogeneity with up to 10-fold variation in incidence between communities. CONCLUSIONS In urban, periurban, and rural communities in and around Kathmandu, we measured a high but heterogenous incidence of typhoid. These findings provide some support for the introduction of conjugate vaccines in Nepal, including outside urban areas, alongside other measures to prevent enteric fever.
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Affiliation(s)
- Dipesh Tamrakar
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | - Krista Vaidya
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | - Alexander T Yu
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, California, USA
| | - Kristen Aiemjoy
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, California, USA
| | - Shiva Ram Naga
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | - Yanjia Cao
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, California, USA
| | - Caryn Bern
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA
| | - Rajeev Shrestha
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | | | - Sailesh Pradhan
- Kathmandu Medical College and Teaching Hospital, Kathmandu, Nepal
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Samir Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children’s) Hospital, Dhaka, Bangladesh
| | - Kashmira Date
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ashley T Longley
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- National Foundation for the Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Caitlin Hemlock
- Applied Epidemiology, Sabin Vaccine Institute, Washington, DC, USA
| | - Stephen Luby
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, California, USA
| | - Denise O Garrett
- Applied Epidemiology, Sabin Vaccine Institute, Washington, DC, USA
| | - Isaac I Bogoch
- Department of Medicine, University of Toronto, Toronto, Canada
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, California, USA
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Antibodies and Protection in Systemic Salmonella Infections: Do We Still Have More Questions than Answers? Infect Immun 2020; 88:IAI.00219-20. [PMID: 32601109 DOI: 10.1128/iai.00219-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Salmonella causes grave systemic infections in humans and other animals and provides a paradigm for other diseases in which the bacteria have both intracellular and extracellular lifestyles. New generations of vaccines rely on the essential contribution of the antibody responses for their protection. The quality, antigen specificity, and functions associated with antibody responses to this pathogen have been elusive for a long time. Recent approaches that combine studies in humans and genetically manipulated experimental models and that exploit awareness of the location and within-host life cycle of the pathogen are shedding light on how humoral immunity to Salmonella operates. However, this area of research remains full of controversy and discrepancies. The overall scenario indicates that antibodies are essential for resistance against systemic Salmonella infections and can express the highest protective function when operating in conjunction with cell-mediated immunity. Antigen specificity, isotype profile, Fc-gamma receptor usage, and complement activation are all intertwined factors that still arcanely influence antibody-mediated protection to Salmonella.
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Islam MT, Im J, Ahmmed F, Kim DR, Khan AI, Zaman K, Ali M, Marks F, Qadri F, Kim JH, Clemens JD. Use of Typhoid Vi-Polysaccharide Vaccine as a Vaccine Probe to Delineate Clinical Criteria for Typhoid Fever. Am J Trop Med Hyg 2020; 103:665-671. [PMID: 32588803 PMCID: PMC7410438 DOI: 10.4269/ajtmh.19-0968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Blood cultures (BCs) detect an estimated 50% of typhoid fever cases. There is need for validated clinical criteria to define cases that are BC negative, both to help direct empiric antibiotic treatment and to better evaluate the magnitude of protection conferred by typhoid vaccines. To derive and validate a clinical rule for defining BC-negative typhoid fever, we assessed, in a cluster-randomized effectiveness trial of Vi-polysaccharide (ViPS) typhoid vaccine in Kolkata, India, 14,797 episodes of fever lasting at least 3 days during 4 years of comprehensive, BC-based surveillance of 70,865 persons. A recursive partitioning algorithm was used to develop a decision rule to predict BC-proven typhoid cases with a diagnostic specificity of 97–98%. To validate this rule as a definition for BC-negative typhoid fever, we assessed whether the rule defined culture-negative syndromes prevented by ViPS vaccine. In a training subset of individuals, we identified the following two rules: rule 1: patients aged < 15 years with prolonged fever accompanied by a measured body temperature ≥ 100°F, headache, and nausea; rule 2: patients aged ≥ 15 years with prolonged fever accompanied by nausea and palpable liver but without constipation. The adjusted protective efficacy of ViPS against clinical typhoid defined by these rules in persons aged ≥ 2 years in a separate validation subset was 33% (95% CI: 4–53%). We have defined and validated a clinical rule for predicting BC-negative typhoid fever using a novel vaccine probe approach. If validated in other settings, this rule may be useful to guide clinical care and to enhance typhoid vaccine evaluations.
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Affiliation(s)
- Md Taufiqul Islam
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Justin Im
- International Vaccine Institute, Seoul, Republic of Korea
| | - Faisal Ahmmed
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Deok Ryun Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Ashraful Islam Khan
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Khalequ Zaman
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Florian Marks
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,International Vaccine Institute, Seoul, Republic of Korea
| | - Firdausi Qadri
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - John D Clemens
- Korea University College of Medicine, Seoul, South Korea.,UCLA Fielding School of Public Health, Los Angeles, California.,International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
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Ali M, Sur D, Kanungo S, Qadri F, Kim DR, Islam T, Im J, Ahmmed F, Chon Y, Khan AI, Zaman K, Marks F, Dutta S, Bhattacharya SK, Clemens JD. Re-evaluating herd protection by Vi typhoid vaccine in a cluster randomized trial. Int Health 2020; 12:36-42. [PMID: 31608962 PMCID: PMC6964216 DOI: 10.1093/inthealth/ihz069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/04/2019] [Accepted: 07/11/2019] [Indexed: 01/14/2023] Open
Abstract
Background In a cluster randomized trial (CRT) of a Vi polysaccharide vaccine against typhoid in the slums of Kolkata we found evidence of vaccine herd protection. However, transmission of typhoid into clusters from the outside likely occurred in this densely populated setting, which could have diminished our estimates of vaccine herd protection. Methods Eighty clusters (40 in each arm) were randomised to receive a single dose of either Vi or inactivated hepatitis A vaccine. We analysed protection for the entire cluster and for subclusters consisting of residents of the innermost households. Results During 2 y of follow-up, total protection was 61% (95% CI 41 to 75), overall protection was 57% (95% CI 37 to 71) and indirect protection was 44% (95% CI 2 to 69). Analyses of the innermost 75% and 50% of households of the clusters showed similar findings. However, in the innermost 25% of households of the clusters, total protection was 82% (95% CI 48 to 94) and overall protection was 66% (95% CI 27 to 84). There was not a sufficient sample size to demonstrate such a trend for indirect protection in these innermost households. Conclusions The findings suggest that analyses of the entire cluster may have led to underestimation of herd protection against typhoid by Vi vaccine and that restriction of the analyses to the inner subclusters may have led to a more accurate estimation of vaccine herd effects.
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Affiliation(s)
- Mohammad Ali
- Johns Hopkins Bloomberg School of Public Health, 615, N Wolfe Street, Baltimore, MD-21205, USA
| | - Dipika Sur
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, Kolkata, India
| | - Suman Kanungo
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, Kolkata, India
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh
| | - Deok Ryun Kim
- International Vaccine Institute, SNU Research Park, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Taufiqul Islam
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh
| | - Justin Im
- International Vaccine Institute, SNU Research Park, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Faisal Ahmmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh
| | - Yun Chon
- International Vaccine Institute, SNU Research Park, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Ashraful Islam Khan
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh
| | - K Zaman
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh
| | - Florian Marks
- International Vaccine Institute, SNU Research Park, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.,Department of Medicine, University of Cambridge, Cambridge, UK
| | - Shanta Dutta
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, Kolkata, India
| | - Sujit K Bhattacharya
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, Kolkata, India
| | - John D Clemens
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani Mohakhali, Dhaka 1212, Bangladesh.,UCLA Fielding School of Public Health, Los Angeles, CA 90095-1772, USA
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15
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O'Reilly PJ, Pant D, Shakya M, Basnyat B, Pollard AJ. Progress in the overall understanding of typhoid fever: implications for vaccine development. Expert Rev Vaccines 2020; 19:367-382. [PMID: 32238006 DOI: 10.1080/14760584.2020.1750375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Typhoid fever continues to have a substantial impact on human health, especially in Asia and sub-Saharan Africa. Access to safe water, and adequate sanitation and hygiene remain the cornerstone of prevention, but these are not widely available in many impoverished settings. The emergence of antibiotic resistance affects typhoid treatment and adds urgency to typhoid control efforts. Vaccines provide opportunities to prevent and control typhoid fever in endemic settings. AREAS COVERED Literature search was performed looking for evidence concerning the global burden of typhoid and strategies for the prevention and treatment of typhoid fever. Cost of illness, available typhoid and paratyphoid vaccines and cost-effectiveness were also reviewed. The objective was to provide a critical overview of typhoid fever, in order to assess the current understanding and potential future directions for typhoid treatment and control. EXPERT COMMENTARY Our understanding of typhoid burden and methods of prevention has grown over recent years. However, typhoid fever still has a significant impact on health in low and middle-income countries. Introduction of typhoid conjugate vaccines to the immunization schedule is expected to make a major contribution to control of typhoid fever in endemic countries, although vaccination alone is unlikely to eliminate the disease.
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Affiliation(s)
- Peter J O'Reilly
- Oxford Vaccine Group, Department of Pediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre , Oxford, UK
| | - Dikshya Pant
- Department of Paediatrics, Patan Academy of Health Sciences, Patan Hospital , Kathmandu, Nepal
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences , Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences , Kathmandu, Nepal
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Pediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre , Oxford, UK
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16
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A phase 1 randomized safety, reactogenicity, and immunogenicity study of Typhax: A novel protein capsular matrix vaccine candidate for the prevention of typhoid fever. PLoS Negl Trop Dis 2020; 14:e0007912. [PMID: 31905228 PMCID: PMC6964911 DOI: 10.1371/journal.pntd.0007912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 01/16/2020] [Accepted: 11/08/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Typhoid fever remains a significant cause of morbidity and mortality in developing countries especially in children ≤5 years old. Although the widely available unconjugated Vi polysaccharide vaccines are efficacious, they confer limited, short-term protection and are not approved for young children or infants. Vi conjugate vaccines, however, are now licensed in several typhoid endemic countries for use in children >6 months of age. As an alternative to conjugate vaccines, Matrivax has applied its novel 'virtual conjugation' Protein Capsular Matrix Vaccine (PCMV) technology to manufacture Typhax, which is composed of Vi polysaccharide entrapped in a cross-linked CRM197 matrix. METHODOLOGY A randomized, double-blinded, dose escalating Phase 1 study was performed to compare the safety and immunogenicity of three dose levels of aluminum phosphate adjuvanted Typhax (0.5, 2.5, or 10 μg of Vi antigen) to the FDA licensed vaccine, Typhim Vi, and placebo. Groups of 15 healthy adult subjects aged 18 to 55 years were randomized and received Typhax, Typhim Vi, or placebo at a ratio of 9:3:3. Typhax and placebo were administered in a two-dose regimen (Days 0 and 28) while Typhim Vi was administered as a single-dose on Day 0 with a placebo administered on Day 28. All doses were administered as a 0.5 mL intramuscular (IM) injection in a blinded fashion. The anti-Vi IgG antibody response was determined preimmunization (Day 0) and on Days 14, 28, 42, and 180 by ELISA. Seroconversion was defined as a titer 4-fold or greater above baseline. PRINCIPAL FINDINGS All Typhax vaccine regimens were well tolerated and adverse events were low in number and primarily characterized as mild in intensity and similar in incidence across the treatment groups. Reactogenicity, primarily pain and tenderness at the injection site, was observed in both the Typhax and Typhim Vi treatment groups; a modest increase in incidence was observed with increasing Typhax doses. Following one dose of Typhax, seroconversion rates at day 28 were 12.5%, 77.8%, 66.7% at the 0.5, 2.5, and 10 μg dose levels, respectively, compared to 55.6% and 0% in the Typhim Vi and placebo groups, respectively. A second dose of Typhax on Day 28 did not elicit a significant increase in GMT or seroconversion at Day 42 or Day 180 at any dose level. CONCLUSIONS Collectively, the results from this randomized phase 1 clinical trial indicate that Typhax is safe, well tolerated, and immunogenic. After a single dose, Typhax at the 2.5 and 10 μg dose levels elicited comparable anti-Vi IgG titers and seroconversion rates as a single dose of Typhim Vi (25 μg dose). A second dose of Typhax at Day 28 did not elicit a booster response. TRIAL REGISTRATION ClinicalTrials.gov NCT03926455.
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17
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AMICIZIA D, MICALE R, PENNATI B, ZANGRILLO F, IOVINE M, LECINI E, MARCHINI F, LAI P, PANATTO D. Burden of typhoid fever and cholera: similarities and differences. Prevention strategies for European travelers to endemic/epidemic areas. JOURNAL OF PREVENTIVE MEDICINE AND HYGIENE 2019; 60:E271-E285. [PMID: 31967084 PMCID: PMC6953460 DOI: 10.15167/2421-4248/jpmh2019.60.4.1333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/04/2019] [Indexed: 11/16/2022]
Abstract
The burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid fever (TF) and cholera are potentially life-threatening infectious diseases, and are mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused by Salmonella typhi, whereas cholera is caused by intestinal infection by the toxin-producing bacterium Vibrio cholerae. These diseases typically affect low- and middle-income countries where housing is overcrowded and water and sanitation are poor, or where conflicts or natural disasters have led to the collapse of the water, sanitation and healthcare systems. Mortality is higher in children under 5 years of age. Regarding their geographical distribution, TF has a high incidence in sub-Saharan Africa, India and south-east Asia, while cholera has a high incidence in a few African countries, particularly in the Horn of Africa and the Arabian Peninsula. In the fight against these diseases, preventive measures are fundamental. With modern air travel, transmissible diseases can spread across continents and oceans in a few days, constituting a threat to global public health. Nowadays, people travel for many reasons, such as tourism and business. Several surveys have shown that a high proportion of travelers lack adequate information on safety issues, such as timely vaccination and prophylactic medications. The main objective of this overview is to provide information to help European travelers to stay healthy while abroad, and thus also to reduce the potential importation of these diseases and their consequent implications for public health and society. The preventive measures to be implemented in the case of travel to countries where these diseases are still endemic are well known: the adoption of safe practices and vaccinations. It is important to stress that an effective preventive strategy should be based both on vaccinations and on hygiene travel guidelines. Furthermore, the emergence of multidrug-resistant strains is becoming a serious problem in the clinical treatment of these diseases. For this reason, vaccination is the main solution.
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Affiliation(s)
| | | | | | | | | | | | | | | | - D. PANATTO
- Department of Health Sciences, University of Genoa, Italy
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18
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Jeon HJ, Pak GD, Im J, Owusu-Dabo E, Adu-Sarkodie Y, Gassama Sow A, Bassiahi Soura A, Gasmelseed N, Keddy KH, Bjerregaard-Andersen M, Konings F, Aseffa A, Crump JA, Chon Y, Breiman RF, Park SE, Cruz Espinoza LM, Seo HJ, May J, Meyer CG, Andrews JR, Panzner U, von Kalckreuth V, Wierzba TF, Rakotozandrindrainy R, Dougan G, Levine MM, Hombach J, Kim JH, Clemens JD, Baker S, Marks F. Determining the Best Immunization Strategy for Protecting African Children Against Invasive Salmonella Disease. Clin Infect Dis 2019; 67:1824-1830. [PMID: 29746615 PMCID: PMC6260167 DOI: 10.1093/cid/ciy386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/27/2018] [Indexed: 12/26/2022] Open
Abstract
Background The World Health Organization recently prequalified a typhoid conjugate vaccine (TCV), recommending its use in persons ≥6 months to 45 years residing in typhoid fever (TF)-endemic areas. We now need to consider how TCVs can have the greatest impact in the most vulnerable populations. Methods The Typhoid Fever Surveillance in Africa Program (TSAP) was a blood culture-based surveillance of febrile patients from defined populations presenting at healthcare facilities in 10 African countries. TF and invasive non-typhoidal Salmonella (iNTS) disease incidences were estimated for 0-10 year-olds in one-year age increments. Results Salmonella Typhi and iNTS were the most frequently isolated pathogens; 135 and 94 cases were identified, respectively. Analysis from three countries was excluded (incomplete person-years of observation (PYO) data). Thirty-seven of 123 TF cases (30.1%) and 71/90 iNTS disease cases (78.9%) occurred in children aged <5 years. No TF and 8/90 iNTS infections (8.9%) were observed in infants aged <9 months. The TF incidences (/100 000 PYO) for children aged <1 year and 1 to <2 years were 5 and 39, respectively; the highest incidence was 304 per 100 000 PYO in 4 to <5 year-olds. The iNTS disease incidence in the defined age groups ranged between 81 and 233 per 100 000 PYO, highest in 1 to <2 year-olds. TF and iNTS disease incidences were higher in West Africa. Conclusions High burden of TF detected in young children strengthens the need for TCV introduction. Given the concurrent iNTS disease burden, development of a trivalent vaccine against S. Typhi, S. Typhimurium, and S. Enteritidis may be timely in this region.
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Affiliation(s)
- Hyon Jin Jeon
- International Vaccine Institute, Seoul, Republic of Korea
| | - Gi Deok Pak
- International Vaccine Institute, Seoul, Republic of Korea
| | - Justin Im
- International Vaccine Institute, Seoul, Republic of Korea
| | - Ellis Owusu-Dabo
- Kumasi Center for Collaborative Research in Tropical Medicine, Kumasi, Ghana.,Departments of Global and International Health, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Yaw Adu-Sarkodie
- Departments of Clinical Microbiology, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Amy Gassama Sow
- Institute Pasteur de Dakar.,Université Cheikh Anta Diop de Dakar, Senegal
| | | | - Nagla Gasmelseed
- Faculty of Medicine, University of Gezira, Wad Medani, Sudan.,Faculty of Science, University of Hafr Al Batin, Saudi Arabia
| | - Karen H Keddy
- National Institute for Communicable Diseases, Johannesburg, South Africa.,Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Morten Bjerregaard-Andersen
- Bandim Health Project, Bissau, Guinea-Bissau.,Research Center for Vitamins and Vaccines, Copenhagen, Denmark
| | - Frank Konings
- International Vaccine Institute, Seoul, Republic of Korea
| | - Abraham Aseffa
- Armauer Hansen Research Institute, ALERT Campus, Addis Ababa, Ethiopia
| | - John A Crump
- Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,Division of Infectious Diseases and International Health, Duke University Medical Center.,Duke Global Health Institute, Duke University, Durham, North Carolina.,Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Yun Chon
- International Vaccine Institute, Seoul, Republic of Korea
| | | | - Se Eun Park
- International Vaccine Institute, Seoul, Republic of Korea.,Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - Hye Jin Seo
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jürgen May
- Bernhard Nocht Institute for Tropical Medicine, Hamburg
| | - Christian G Meyer
- Institute of Tropical Medicine, Eberhard-Karls University Tübingen, Germany.,Duy Tan University, Da Nang, Vietnam
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University, California
| | - Ursula Panzner
- International Vaccine Institute, Seoul, Republic of Korea
| | | | | | | | - Gordon Dougan
- Department of Medicine, University of Cambridge, United Kingdom
| | - Myron M Levine
- Department of Medicine, University of Maryland School of Medicine, Baltimore
| | | | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - John D Clemens
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka.,Fielding School of Public Health, University of California, Los Angeles.,Korea University School of Medicine, Seoul, Republic of Korea
| | - Stephen Baker
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Department of Medicine, University of Cambridge, United Kingdom
| | - Florian Marks
- International Vaccine Institute, Seoul, Republic of Korea.,Department of Medicine, University of Cambridge, United Kingdom
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19
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Marchello CS, Dale AP, Pisharody S, Crump JA. Using hospital-based studies of community-onset bloodstream infections to make inferences about typhoid fever incidence. Trop Med Int Health 2019; 24:1369-1383. [PMID: 31633858 PMCID: PMC6916262 DOI: 10.1111/tmi.13319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Objectives Hospital-based studies of community-onset bloodstream infections (CO-BSI) are less resource-intensive to carry out than population-based incidence studies. We examined several metrics capturing the potential role of Salmonella Typhi as a cause of CO-BSI for making inferences about incidence. Methods We systematically reviewed three databases for hospital-based studies of CO-BSI. We determined, by study, the prevalence and rank order of Salmonella among pathogenic bloodstream isolates, and the prevalence ratio of Salmonella Typhi to Escherichia coli (S:E ratio). We then describe these hospital-based study metrics in relation to population-based typhoid fever incidence data from a separate systematic review. Results Forty-four studies met the inclusion criteria, of which 23 (52.3%) isolated Salmonella Typhi at least once. Among studies isolating Salmonella Typhi, the median (interquartile range) prevalence and rank order of Salmonella Typhi compared to other pathogens isolated in BSI was 8.3% (3.2–37.9%) and 3 (1–6), respectively. The median (interquartile range) S:E ratio was 1.0 (0.4–3.0). With respect to incidence, in Pemba Island, Tanzania, prevalence, rank order, S:E ratio, and incidence was 64.8%, 1, 9.2 and 110 cases per 100 000, respectively, and in Boulkiemdé, Burkina Faso, was 13.3%, 3, 2.3 and 249 cases per 100 000. Conclusions We describe considerable variation in place and time for Salmonella Typhi prevalence, rank order, and S:E ratio among hospital-based studies of CO-BSI. Data from simultaneous typhoid prevalence and incidence studies are limited. We propose that hospital-based study metrics warrant evaluation for making inference about typhoid incidence and as covariates in typhoid incidence models.
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Affiliation(s)
| | - Ariella P Dale
- Colorado Department of Public Health and Environment, Denver, CO, USA
| | | | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
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20
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Pitzer VE, Meiring J, Martineau FP, Watson CH, Kang G, Basnyat B, Baker S. The Invisible Burden: Diagnosing and Combatting Typhoid Fever in Asia and Africa. Clin Infect Dis 2019; 69:S395-S401. [PMID: 31612938 PMCID: PMC6792124 DOI: 10.1093/cid/ciz611] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Measuring the burden of typhoid fever and developing effective strategies to reduce it require a surveillance infrastructure that is currently lacking in many endemic countries. Recent efforts and partnerships between local and international researchers have helped to provide new data on the incidence and control of typhoid in parts of Asia and Africa. Here, we highlight examples from India, Nepal, Vietnam, Fiji, Sierra Leone, and Malawi that summarize past and present experiences with the diagnosis, treatment, and prevention of typhoid fever in different locations with endemic disease. While there is no validated road map for the elimination of typhoid, the lessons learned in studying the epidemiology and control of typhoid in these settings can provide insights to guide future disease control efforts.
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Affiliation(s)
- Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - James Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
| | | | - Conall H Watson
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, United Kingdom
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Gagandeep Kang
- Translational Health Sciences Technology Institute, Faridabad, Haryana, India
| | - Buddha Basnyat
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Medicine, University of Cambridge, United Kingdom
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21
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Micoli F, Del Bino L, Alfini R, Carboni F, Romano MR, Adamo R. Glycoconjugate vaccines: current approaches towards faster vaccine design. Expert Rev Vaccines 2019; 18:881-895. [PMID: 31475596 DOI: 10.1080/14760584.2019.1657012] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Over the last decades, glycoconjugate vaccines have been proven to be a successful strategy to prevent infectious diseases. Many diseases remain to be controlled, especially in developing countries, and emerging antibiotic-resistant bacteria present an alarming public-health threat. The increasing complexity of future vaccines, and the need to accelerate development processes have triggered the development of faster approaches to glycoconjugate vaccines design. Areas covered: This review provides an overview of recent progress in glycoconjugation technologies toward faster vaccine design. Expert opinion: Among the different emerging approaches, glycoengineering has the potential to combine glycan assembly and conjugation to carrier systems (such as proteins or outer membrane vesicles) in one step, resulting in a simplified manufacturing process and fewer analytical controls. Chemical and enzymatic strategies, and their automation can facilitate glycoepitope identification for vaccine design. Other approaches, such as the liposomal encapsulation of polysaccharides, potentially enable fast and easy combination of numerous antigens in the same formulation. Additional progress is envisaged in the near future, and some of these systems still need to be further validated in humans. In parallel, new strategies are needed to accelerate the vaccine development process, including the associated clinical trials, up to vaccine release onto the market.
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Affiliation(s)
- Francesca Micoli
- Technology Platform, GSK Vaccines Institute for Global Health s.r.l , Siena , Italy
| | | | - Renzo Alfini
- Technology Platform, GSK Vaccines Institute for Global Health s.r.l , Siena , Italy
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22
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Koirala KD, Chappuis F, Verdonck K, Rijal S, Boelaert M. Persistent febrile illnesses in Nepal: A systematic review. Indian J Med Res 2019; 148:385-395. [PMID: 30666001 PMCID: PMC6362719 DOI: 10.4103/ijmr.ijmr_505_18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Background & objectives Although febrile illnesses are a frequent cause of consultation and hospitalization in low- and middle-income countries (LMICs), research has mainly focused on acute febrile illnesses (AFIs). In contrast, there are limited data on the causes of persistent febrile illnesses (PFIs) in LMIC. Lack of clarity on the differential diagnosis of PFIs in the rural tropics leads to the absence of diagnostic guidance tools. Methods In this study, a review of the potential causes of persistent fever defined as fever of more than seven days was done in Nepal, with a focus on nine pathogen-specific conditions. The current knowledge on their burden, distribution and diagnosis was summarized. Results Limited data were found on the incidence and public health burden of leptospirosis, murine typhus and brucellosis due to the absence of diagnostic tools outside reference laboratories and the overlap of signs and symptoms with other febrile conditions. The incidence of malaria and visceral leishmaniasis (VL) was found to be decreasing in Nepal, with some changes of the geographical areas at risk. Interpretation & conclusions This review indicates a need for more research on the causes of PFIs in Nepal and in the region and for the development of clinical guidance tailored to current local epidemiology. Guidance tools should include specific clinical features (e.g. eschar), results of rapid diagnostic tests (e.g. malaria, VL), appropriate indications for more sophisticated tests (e.g. abdominal ultrasound, polymerase chain reaction) and recommendations for adequate use of empirical treatment.
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Affiliation(s)
- Kanika Deshpande Koirala
- Department of Medicine, B.P. Koirala Institute of Health Science, Dharan, Nepal; Epidemiology and Control of Neglected Tropical Diseases Unit, Institute of Tropical Medicine, Antwerp, Belgium; Institute of Global Health, University of Geneva, Geneva, Switzerland
| | - François Chappuis
- Institute of Global Health, University of Geneva; Division of Tropical & Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Kristien Verdonck
- Epidemiology and Control of Neglected Tropical Diseases Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Suman Rijal
- Department of Medicine, B.P. Koirala Institute of Health Science, Dharan, Nepal
| | - Marleen Boelaert
- Epidemiology and Control of Neglected Tropical Diseases Unit, Institute of Tropical Medicine, Antwerp, Belgium
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23
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Abstract
BACKGROUND Contemporary incidence estimates of typhoid fever are needed to guide policy decisions and control measures and to improve future epidemiological studies. METHODS We systematically reviewed 3 databases (Ovid Medline, PubMed, and Scopus) without restriction on age, country, language, or time for studies reporting the incidence of blood culture-confirmed typhoid fever. Outbreak, travel-associated, and passive government surveillance reports were excluded. We performed a meta-analysis using a random-effects model to calculate estimates of pooled incidence, stratifying by studies that reported the incidence of typhoid fever and those that estimated incidence by using multipliers. RESULTS Thirty-three studies were included in the analysis. There were 26 study sites from 16 countries reporting typhoid cases from population-based incidence studies, and 17 sites in 9 countries used multipliers to account for underascertainment in sentinel surveillance data. We identified Africa and Asia as regions with studies showing high typhoid incidence while noting considerable variation of typhoid incidence in time and place, including in consecutive years at the same location. Overall, more recent studies reported lower typhoid incidence compared to years prior to 2000. We identified variation in the criteria for collecting a blood culture, and among multiplier studies we identified a lack of a standardization for the types of multipliers being used to estimate incidence. CONCLUSIONS Typhoid fever incidence remains high at many sites. Additional and more accurate typhoid incidence studies are needed to support country decisions about typhoid conjugate vaccine adoption. Standardization of multiplier types applied in multiplier studies is recommended.
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Affiliation(s)
| | - Chuen Yen Hong
- Centre for International Health, University of Otago, New Zealand
| | - John A Crump
- Centre for International Health, University of Otago, New Zealand
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24
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Radhakrishnan A, Als D, Mintz ED, Crump JA, Stanaway J, Breiman RF, Bhutta ZA. Introductory Article on Global Burden and Epidemiology of Typhoid Fever. Am J Trop Med Hyg 2018; 99:4-9. [PMID: 30047370 PMCID: PMC6128367 DOI: 10.4269/ajtmh.18-0032] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
This article is the introduction to a 12-paper supplement on global trends in typhoid fever. The Tackling Typhoid (T2) project was initiated in 2015 to synthesize the existing body of literature on typhoidal salmonellae and study national and regional typhoid fever trends. In addition to a global systematic review, eight case studies were undertaken to examine typhoid and paratyphoid fever trends in endemic countries alongside changes in relevant contextual factors. Incidence variations exist both within and between regions with large subnational differences as well, suggesting that public health changes impacting typhoid and paratyphoid fevers in one setting may not have similar impacts in another. This supplement also brings to light the lack of national typhoid fever surveillance systems, inconsistencies in diagnostics, and the lack of typhoid fever associated morbidity and mortality data in many countries, making it difficult to accurately quantify and track burden of disease. To better understand typhoid fever there is a need for more high-quality data from resource-poor settings. The implementation of typhoid surveillance systems alongside the transition to blood-culture confirmation of cases, where possible, would aid in the improvement of data quality in low-income settings. The following supplement includes the results of our global systematic review, eight-country case study articles, a qualitative article informed by semistructured interviews, and a conclusion article on potential ways forward for typhoid control.
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Affiliation(s)
| | - Daina Als
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - Eric D Mintz
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Jefferey Stanaway
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - Zulfiqar A Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada.,Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan.,Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
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Abstract
BACKGROUND Typhoid fever and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and southeast Asia. Two typhoid vaccines are widely available, Ty21a (oral) and Vi polysaccharide (parenteral). Newer typhoid conjugate vaccines are at varying stages of development and use. The World Health Organization has recently recommended a Vi tetanus toxoid (Vi-TT) conjugate vaccine, Typbar-TCV, as the preferred vaccine for all ages. OBJECTIVES To assess the effects of vaccines for preventing typhoid fever. SEARCH METHODS In February 2018, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, and mRCT. We also searched the reference lists of all included trials. SELECTION CRITERIA Randomized and quasi-randomized controlled trials (RCTs) comparing typhoid fever vaccines with other typhoid fever vaccines or with an inactive agent (placebo or vaccine for a different disease) in adults and children. Human challenge studies were not eligible. DATA COLLECTION AND ANALYSIS Two review authors independently applied inclusion criteria and extracted data, and assessed the certainty of the evidence using the GRADE approach. We computed vaccine efficacy per year of follow-up and cumulative three-year efficacy, stratifying for vaccine type and dose. The outcome addressed was typhoid fever, defined as isolation of Salmonella enterica serovar Typhi in blood. We calculated risk ratios (RRs) and efficacy (1 - RR as a percentage) with 95% confidence intervals (CIs). MAIN RESULTS In total, 18 RCTs contributed to the quantitative analysis in this review: 13 evaluated efficacy (Ty21a: 5 trials; Vi polysaccharide: 6 trials; Vi-rEPA: 1 trial; Vi-TT: 1 trial), and 9 reported on adverse events. All trials but one took place in typhoid-endemic countries. There was no information on vaccination in adults aged over 55 years of age, pregnant women, or travellers. Only one trial included data on children under two years of age.Ty21a vaccine (oral vaccine, three doses)A three-dose schedule of Ty21a vaccine probably prevents around half of typhoid cases during the first three years after vaccination (cumulative efficacy 2.5 to 3 years: 50%, 95% CI 35% to 61%, 4 trials, 235,239 participants, moderate-certainty evidence). These data include patients aged 3 to 44 years.Compared with placebo, this vaccine probably does not cause more vomiting, diarrhoea, nausea or abdominal pain (2 trials, 2066 participants; moderate-certainty evidence), headache, or rash (1 trial, 1190 participants; moderate-certainty evidence); however, fever (2 trials, 2066 participants; moderate-certainty evidence) is probably more common following vaccination.Vi polysaccharide vaccine (injection, one dose)A single dose of Vi polysaccharide vaccine prevents around two-thirds of typhoid cases in the first year after vaccination (year 1: 69%, 95% CI 63% to 74%; 3 trials, 99,979 participants; high-certainty evidence). In year 2, trial results were more variable, with the vaccine probably preventing between 45% and 69% of typhoid cases (year 2: 59%, 95% CI 45% to 69%; 4 trials, 194,969 participants; moderate-certainty evidence). These data included participants aged 2 to 55 years of age.The three-year cumulative efficacy of the vaccine may be around 55% (95% CI 30% to 70%; 11,384 participants, 1 trial; low-certainty evidence). These data came from a single trial conducted in South Africa in the 1980s in participants aged 5 to 15 years.Compared with placebo, this vaccine probably did not increase the incidence of fever (3 trials, 132,261 participants; moderate-certainty evidence) or erythema (3 trials, 132,261 participants; low-certainty evidence); however, swelling (3 trials, 1767 participants; moderate-certainty evidence) and pain at the injection site (1 trial, 667 participants; moderate-certainty evidence) were more common in the vaccine group.Vi-rEPA vaccine (two doses)Administration of two doses of the Vi-rEPA vaccine probably prevents between 50% and 96% of typhoid cases during the first two years after vaccination (year 1: 94%, 95% CI 75% to 99%; year 2: 87%, 95% CI 56% to 96%, 1 trial, 12,008 participants; moderate-certainty evidence). These data came from a single trial with children two to five years of age conducted in Vietnam.Compared with placebo, both the first and the second dose of this vaccine increased the risk of fever (1 trial, 12,008 and 11,091 participants, low-certainty evidence) and the second dose increase the incidence of swelling at the injection site (one trial, 11,091 participants, moderate-certainty evidence).Vi-TT vaccine (two doses)We are uncertain of the efficacy of administration of two doses of Vi-TT (PedaTyph) in typhoid cases in children during the first year after vaccination (year 1: 94%, 95% CI -1% to 100%, 1 trial, 1625 participants; very low-certainty evidence). These data come from a single cluster-randomized trial in children aged six months to 12 years and conducted in India. For single dose Vi-TT (Typbar-TCV), we found no efficacy trials evaluating the vaccine with natural exposure.There were no reported serious adverse effects in RCTs of any of the vaccines studied. AUTHORS' CONCLUSIONS The licensed Ty21a and Vi polysaccharide vaccines are efficacious in adults and children older than two years in endemic countries. The Vi-rEPA vaccine is just as efficacious, although data is only available for children. The new Vi-TT vaccine (PedaTyph) requires further evaluation to determine if it provides protection against typhoid fever. At the time of writing, there were only efficacy data from a human challenge setting in adults on the Vi-TT vaccine (Tybar), which clearly justify the ongoing field trials to evaluate vaccine efficacy.
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Affiliation(s)
- Rachael Milligan
- Liverpool School of Tropical MedicineCochrane Infectious Diseases GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Mical Paul
- Rambam Health Care CampusDivision of Infectious DiseasesHa‐aliya 8 StHaifaIsrael33705
| | - Marty Richardson
- Liverpool School of Tropical MedicineCochrane Infectious Diseases GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Ami Neuberger
- Rambam Health Care Campus and The Ruth and Bruce Rappaport Faculty of Medicine, Technion – Israel Institute of TechnologyDivision of Infectious DiseasesTel AvivIsrael
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26
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Parker AR, Bradley C, Harding S, Sánchez-Ramón S, Jolles S, Kiani-Alikhan S. Measurement and interpretation of Salmonella typhi Vi IgG antibodies for the assessment of adaptive immunity. J Immunol Methods 2018; 459:1-10. [PMID: 29800575 DOI: 10.1016/j.jim.2018.05.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/26/2018] [Accepted: 05/21/2018] [Indexed: 01/15/2023]
Abstract
Response to polysaccharide vaccination can be an invaluable tool for assessing functionality of the adaptive immune system. Measurement of antibodies raised in response to Pneumovax®23 is the current gold standard test, but there are significant challenges and constraints in both the measurement and interpretation of the response. An alternative polysaccharide vaccine approach (Salmonella typhi Vi capsule (ViCPS)) has been suggested. In the present article, we review current evidence for the measurement of ViCPS antibodies in the diagnosis of primary and secondary antibody deficiencies. In particular, we review emerging data suggesting their interpretation in combination with the response to Pneumovax®23 and comment upon the utility of these vaccines to assess humoral immune responses while receiving immunoglobulin replacement therapy (IGRT).
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Affiliation(s)
| | | | | | - Silvia Sánchez-Ramón
- Department of Clinical Immunology Hospital Universitario Clínico San Carlos, Madrid, Spain
| | - Stephen Jolles
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK
| | - Sorena Kiani-Alikhan
- Department of Immunology, Barts and The London National Health Service Trust, London, UK
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27
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Hiyoshi H, Tiffany CR, Bronner DN, Bäumler AJ. Typhoidal Salmonella serovars: ecological opportunity and the evolution of a new pathovar. FEMS Microbiol Rev 2018; 42:527-541. [DOI: 10.1093/femsre/fuy024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/19/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Hirotaka Hiyoshi
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Connor R Tiffany
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Denise N Bronner
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
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Zuckerman JN, Hatz C, Kantele A. Review of current typhoid fever vaccines, cross-protection against paratyphoid fever, and the European guidelines. Expert Rev Vaccines 2018; 16:1029-1043. [PMID: 28856924 DOI: 10.1080/14760584.2017.1374861] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Typhoid and paratyphoid fever remain a global health problem, which - in non-endemic countries - are mainly seen in travelers, particularly in VFRs (visiting friends and relatives), with occasional local outbreaks occurring. A rise in anti-microbial resistance emphasizes the role of preventive measures, especially vaccinations against typhoid and paratyphoid fever for travelers visiting endemic countries. Areas covered: This state-of-the-art review recapitulates the epidemiology and mechanisms of disease of typhoid and paratyphoid fever, depicts the perspective of non-endemic countries and travelers (VFRs), and collectively presents current European recommendations for typhoid fever vaccination. We provide a brief overview of available (and developmental) vaccines in Europe, present current data on cross-protection to S. Paratyphi, and aim to provide a background for typhoid vaccine decision-making in travelers. Expert commentary: European recommendations are not harmonized. Experts must assess vaccination of travelers based on current country-specific recommendations. Travel health practitioners should be aware of the issues surrounding vaccination of travelers and be motivated to increase awareness of typhoid and paratyphoid fever risks.
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Affiliation(s)
- Jane N Zuckerman
- a Department of Infection and Immunity , Royal Free London Travel Health and Immunisation Clinic , London , UK
| | - Christoph Hatz
- b Department of Medicine and Diagnostics , Swiss Tropical and Public Health Institute , Basel , Switzerland.,c Epidemiology, Biostatistics and Prevention Institute , University of Zurich , Zurich , Switzerland
| | - Anu Kantele
- d Department of Clinical Medicine , University of Helsinki , Helsinki , Finland.,e Inflammation Center, Division of Infectious Diseases , Helsinki University Hospital , Helsinki , Finland.,f Unit of Infectious Diseases , Karolinska Institutet , Stockholm , Sweden
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29
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Evans C, Bateman E, Steven R, Ponsford M, Cullinane A, Shenton C, Duthie G, Conlon C, Jolles S, Huissoon AP, Longhurst HJ, Rahman T, Scott C, Wallis G, Harding S, Parker AR, Ferry BL. Measurement of Typhi Vi antibodies can be used to assess adaptive immunity in patients with immunodeficiency. Clin Exp Immunol 2018; 192:292-301. [PMID: 29377063 PMCID: PMC5980364 DOI: 10.1111/cei.13105] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2017] [Indexed: 02/06/2023] Open
Abstract
Vaccine‐specific antibody responses are essential in the diagnosis of antibody deficiencies. Responses to Pneumovax II are used to assess the response to polysaccharide antigens, but interpretation may be complicated. Typhim Vi®, a polysaccharide vaccine for Salmonella typhoid fever, may be an additional option for assessing humoral responses in patients suspected of having an immunodeficiency. Here we report a UK multi‐centre study describing the analytical and clinical performance of a Typhi Vi immunoglobulin (Ig)G enzyme‐linked immunosorbent assay (ELISA) calibrated to an affinity‐purified Typhi Vi IgG preparation. Intra‐ and interassay imprecision was low and the assay was linear, between 7·4 and 574 U/ml (slope = 0·99–1·00; R2 > 0·99); 71% of blood donors had undetectable Typhi Vi IgG antibody concentrations. Of those with antibody concentrations > 7·4 U/ml, the concentration range was 7·7–167 U/ml. In antibody‐deficient patients receiving antibody replacement therapy the median Typhi Vi IgG antibody concentrations were < 25 U/ml. In vaccinated normal healthy volunteers, the median concentration post‐vaccination was 107 U/ml (range 31–542 U/ml). Eight of eight patients (100%) had post‐vaccination concentration increases of at least threefold and six of eight (75%) of at least 10‐fold. In an antibody‐deficient population (n = 23), only 30% had post‐vaccination concentration increases of at least threefold and 10% of at least 10‐fold. The antibody responses to Pneumovax II and Typhim Vi® correlated. We conclude that IgG responses to Typhim Vi® vaccination can be measured using the VaccZyme Salmonella typhi Vi IgG ELISA, and that measurement of these antibodies maybe a useful additional test to accompany Pneumovax II responses for the assessment of antibody deficiencies.
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Affiliation(s)
- C Evans
- Clinical Immunology Laboratory, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - E Bateman
- Clinical Immunology Laboratory, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - R Steven
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK
| | - M Ponsford
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK
| | - A Cullinane
- Clinical Immunology Laboratory, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - C Shenton
- Clinical Immunology Laboratory, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - G Duthie
- Infectious Disease Department, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - C Conlon
- Infectious Disease Department, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - S Jolles
- Immunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UK
| | - A P Huissoon
- West Midlands Primary Immunodeficiency Centre, Birmingham Heartlands Hospital, Birmingham, UK
| | - H J Longhurst
- Department of Immunology, Barts Health NHS Trust, London, UK
| | - T Rahman
- Department of Immunology, Barts Health NHS Trust, London, UK
| | - C Scott
- Department of Immunology, Barts Health NHS Trust, London, UK
| | - G Wallis
- Binding Site Group Limited, Birmingham, UK
| | - S Harding
- Binding Site Group Limited, Birmingham, UK
| | - A R Parker
- Binding Site Group Limited, Birmingham, UK
| | - B L Ferry
- Clinical Immunology Laboratory, Oxford University Hospitals Foundation Trust, Oxford, UK
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30
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Rey-Jurado E, Tapia F, Muñoz-Durango N, Lay MK, Carreño LJ, Riedel CA, Bueno SM, Genzel Y, Kalergis AM. Assessing the Importance of Domestic Vaccine Manufacturing Centers: An Overview of Immunization Programs, Vaccine Manufacture, and Distribution. Front Immunol 2018; 9:26. [PMID: 29403503 PMCID: PMC5778105 DOI: 10.3389/fimmu.2018.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 01/04/2018] [Indexed: 12/03/2022] Open
Abstract
Vaccines have significantly reduced the detrimental effects of numerous human infectious diseases worldwide, helped to reduce drastically child mortality rates and even achieved eradication of major pathogens, such as smallpox. These achievements have been possible due to a dedicated effort for vaccine research and development, as well as an effective transfer of these vaccines to public health care systems globally. Either public or private institutions have committed to developing and manufacturing vaccines for local or international population supply. However, current vaccine manufacturers worldwide might not be able to guarantee sufficient vaccine supplies for all nations when epidemics or pandemics events could take place. Currently, different countries produce their own vaccine supplies under Good Manufacturing Practices, which include the USA, Canada, China, India, some nations in Europe and South America, such as Germany, the Netherlands, Italy, France, Argentina, and Brazil, respectively. Here, we discuss some of the vaccine programs and manufacturing capacities, comparing the current models of vaccine management between industrialized and developing countries. Because local vaccine production undoubtedly provides significant benefits for the respective population, the manufacture capacity of these prophylactic products should be included in every country as a matter of national safety.
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Affiliation(s)
- Emma Rey-Jurado
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Tapia
- Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Natalia Muñoz-Durango
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Margarita K. Lay
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Leandro J. Carreño
- Millennium Institute on Immunology and Immunotherapy, Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Claudia A. Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas y Facultad de Medicina, Universidad Andrés Bello, Santiago, Chile
| | - Susan M. Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Yvonne Genzel
- Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Zhang GL, Wei MM, Song C, Ma YF, Zheng XJ, Xiong DC, Ye XS. Chemical synthesis and biological evaluation of penta- to octa- saccharide fragments of Vi polysaccharide fromSalmonella typhi. Org Chem Front 2018. [DOI: 10.1039/c8qo00471d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The penta- to octa-saccharide fragments of Vi polysaccharide were synthesized efficiently, and the hexasaccharide might be the minimum epitope of Vi antigen based on ELISA analysis.
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Affiliation(s)
- Gao-Lan Zhang
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
| | - Meng-Man Wei
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
| | - Chengcheng Song
- School of Life Sciences
- Northeast Normal University
- Changchun 130024
- China
| | - Yu-Feng Ma
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
| | - Xiu-Jing Zheng
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
| | - De-Cai Xiong
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
| | - Xin-Shan Ye
- State Key Laboratory of Natural and Biomimetic Drugs
- School of Pharmaceutical Sciences
- Peking University
- Beijing 100191
- China
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Jin C, Gibani MM, Moore M, Juel HB, Jones E, Meiring J, Harris V, Gardner J, Nebykova A, Kerridge SA, Hill J, Thomaides-Brears H, Blohmke CJ, Yu LM, Angus B, Pollard AJ. Efficacy and immunogenicity of a Vi-tetanus toxoid conjugate vaccine in the prevention of typhoid fever using a controlled human infection model of Salmonella Typhi: a randomised controlled, phase 2b trial. Lancet 2017; 390:2472-2480. [PMID: 28965718 PMCID: PMC5720597 DOI: 10.1016/s0140-6736(17)32149-9] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/20/2017] [Accepted: 07/26/2017] [Indexed: 12/03/2022]
Abstract
BACKGROUND Salmonella enterica serovar Typhi (S Typhi) is responsible for an estimated 20 million infections and 200 000 deaths each year in resource poor regions of the world. Capsular Vi-polysaccharide-protein conjugate vaccines (Vi-conjugate vaccines) are immunogenic and can be used from infancy but there are no efficacy data for the leading candidate vaccine being considered for widespread use. To address this knowledge gap, we assessed the efficacy of a Vi-tetanus toxoid conjugate vaccine using an established human infection model of S Typhi. METHODS In this single-centre, randomised controlled, phase 2b study, using an established outpatient-based human typhoid infection model, we recruited healthy adult volunteers aged between 18 and 60 years, with no previous history of typhoid vaccination, infection, or prolonged residency in a typhoid-endemic region. Participants were randomly assigned (1:1:1) to receive a single dose of Vi-conjugate (Vi-TT), Vi-polysaccharide (Vi-PS), or control meningococcal vaccine with a computer-generated randomisation schedule (block size 6). Investigators and participants were masked to treatment allocation, and an unmasked team of nurses administered the vaccines. Following oral ingestion of S Typhi, participants were assessed with daily blood culture over a 2-week period and diagnosed with typhoid infection when meeting pre-defined criteria. The primary endpoint was the proportion of participants diagnosed with typhoid infection (ie, attack rate), defined as persistent fever of 38°C or higher for 12 h or longer or S Typhi bacteraemia, following oral challenge administered 1 month after Vi-vaccination (Vi-TT or Vi-PS) compared with control vaccination. Analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT02324751, and is ongoing. FINDINGS Between Aug 18, 2015, and Nov 4, 2016, 112 participants were enrolled and randomly assigned; 34 to the control group, 37 to the Vi-PS group, and 41 to the Vi-TT group. 103 participants completed challenge (31 in the control group, 35 in the Vi-PS group, and 37 in the Vi-TT group) and were included in the per-protocol population. The composite criteria for typhoid diagnosis was met in 24 (77%) of 31 participants in the control group, 13 (35%) of 37 participants in the Vi-TT group, and 13 (35%) of 35 participants in the Vi-PS group to give vaccine efficacies of 54·6% (95% CI 26·8-71·8) for Vi-TT and 52·0% (23·2-70·0) for Vi-PS. Seroconversion was 100% in Vi-TT and 88·6% in Vi-PS participants, with significantly higher geometric mean titres detected 1-month post-vaccination in Vi-TT vaccinees. Four serious adverse events were reported during the conduct of the study, none of which were related to vaccination (one in the Vi-TT group and three in the Vi-PS group). INTERPRETATION Vi-TT is a highly immunogenic vaccine that significantly reduces typhoid fever cases when assessed using a stringent controlled model of typhoid infection. Vi-TT use has the potential to reduce both the burden of typhoid fever and associated health inequality. FUNDING The Bill & Melinda Gates Foundation and the European Commission FP7 grant, Advanced Immunization Technologies (ADITEC).
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Affiliation(s)
- Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK.
| | - Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Maria Moore
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Helene B Juel
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - James Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Victoria Harris
- Nuffield Department of Primary Care Health Sciences, University of Oxford, UK
| | - Jonathan Gardner
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Anna Nebykova
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Simon A Kerridge
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Helena Thomaides-Brears
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Ly-Mee Yu
- Nuffield Department of Primary Care Health Sciences, University of Oxford, UK
| | - Brian Angus
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - 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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Lee SJ, Benoun J, Sheridan BS, Fogassy Z, Pham O, Pham QM, Puddington L, McSorley SJ. Dual Immunization with SseB/Flagellin Provides Enhanced Protection against Salmonella Infection Mediated by Circulating Memory Cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 199:1353-1361. [PMID: 28710253 PMCID: PMC5548602 DOI: 10.4049/jimmunol.1601357] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 06/19/2017] [Indexed: 01/09/2023]
Abstract
The development of a subunit Salmonella vaccine has been hindered by the absence of detailed information about antigenic targets of protective Salmonella-specific T and B cells. Recent studies have identified SseB as a modestly protective Ag in susceptible C57BL/6 mice, but the mechanism of protective immunity remains undefined. In this article, we report that simply combining Salmonella SseB with flagellin substantially enhances protective immunity, allowing immunized C57BL/6 mice to survive for up to 30 d following challenge with virulent bacteria. Surprisingly, the enhancing effect of flagellin did not require flagellin Ag targeting during secondary responses or recognition of flagellin by TLR5. Although coimmunization with flagellin did not affect SseB-specific Ab responses, it modestly boosted CD4 responses. In addition, protective immunity was effectively transferred in circulation to parabionts of immunized mice, demonstrating that tissue-resident memory is not required for vaccine-induced protection. Finally, protective immunity required host expression of IFN-γR but was independent of induced NO synthase expression. Taken together, these data indicate that Salmonella flagellin has unique adjuvant properties that improve SseB-mediated protective immunity provided by circulating memory.
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Affiliation(s)
- Seung-Joo Lee
- Center for Comparative Medicine, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616; and
| | - Joseph Benoun
- Center for Comparative Medicine, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616; and
| | - Brian S Sheridan
- Department of Immunology, University of Connecticut Health Center, Farmington, CT 06030
| | - Zachary Fogassy
- Center for Comparative Medicine, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616; and
| | - Oanh Pham
- Center for Comparative Medicine, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616; and
| | - Quynh-Mai Pham
- Department of Immunology, University of Connecticut Health Center, Farmington, CT 06030
| | - Lynn Puddington
- Department of Immunology, University of Connecticut Health Center, Farmington, CT 06030
| | - Stephen J McSorley
- Center for Comparative Medicine, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616;
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616; and
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Kurtz JR, Goggins JA, McLachlan JB. Salmonella infection: Interplay between the bacteria and host immune system. Immunol Lett 2017; 190:42-50. [PMID: 28720334 DOI: 10.1016/j.imlet.2017.07.006] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 12/14/2022]
Abstract
Salmonella infection causes morbidity and mortality throughout the world with the host immune response varying depending on whether the infection is acute and limited, or systemic and chronic. Additionally, Salmonella bacteria have evolved multiple mechanisms to avoid or subvert immunity to its own benefit and often the anatomical location of infection plays a role in both the immune response and bacterial fate. Here, we provide an overview of the interplay between the immune system and Salmonella, while discussing how different host and bacterial factors influence the outcome of infection.
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Affiliation(s)
- Jonathan R Kurtz
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States
| | - J Alan Goggins
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States
| | - James B McLachlan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States.
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Mogasale V, Ramani E, Park IY, Lee JS. A forecast of typhoid conjugate vaccine introduction and demand in typhoid endemic low- and middle-income countries to support vaccine introduction policy and decisions. Hum Vaccin Immunother 2017; 13:2017-2024. [PMID: 28604164 PMCID: PMC5612352 DOI: 10.1080/21645515.2017.1333681] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
A Typhoid Conjugate Vaccine (TCV) is expected to acquire WHO prequalification soon, which will pave the way for its use in many low- and middle-income countries where typhoid fever is endemic. Thus it is critical to forecast future vaccine demand to ensure supply meets demand, and to facilitate vaccine policy and introduction planning. We forecasted introduction dates for countries based on specific criteria and estimated vaccine demand by year for defined vaccination strategies in 2 scenarios: rapid vaccine introduction and slow vaccine introduction. In the rapid introduction scenario, we forecasted 17 countries and India introducing TCV in the first 5 y of the vaccine's availability while in the slow introduction scenario we forecasted 4 countries and India introducing TCV in the same time period. If the vaccine is targeting infants in high-risk populations as a routine single dose, the vaccine demand peaks around 40 million doses per year under the rapid introduction scenario. Similarly, if the vaccine is targeting infants in the general population as a routine single dose, the vaccine demand increases to 160 million doses per year under the rapid introduction scenario. The demand forecast projected here is an upper bound estimate of vaccine demand, where actual demand depends on various factors such as country priorities, actual vaccine introduction, vaccination strategies, Gavi financing, costs, and overall product profile. Considering the potential role of TCV in typhoid control globally; manufacturers, policymakers, donors and financing bodies should work together to ensure vaccine access through sufficient production capacity, early WHO prequalification of the vaccine, continued Gavi financing and supportive policy.
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Affiliation(s)
- Vittal Mogasale
- a International Vaccine Institute , Policy and Economic Research Department , Gwanak-gu , Seoul , South Korea
| | - Enusa Ramani
- b International Vaccine Institute , Policy and Economic Research Department , Gwanak-gu , Seoul , South Korea
| | - Il Yeon Park
- c International Vaccine Institute , Policy and Economic Research Department , Gwanak-gu , Seoul , South Korea
| | - Jung Seok Lee
- d International Vaccine Institute , Policy and Economic Research Department , Gwanak-gu , Seoul , South Korea
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Xiong K, Zhu C, Chen Z, Zheng C, Tan Y, Rao X, Cong Y. Vi Capsular Polysaccharide Produced by Recombinant Salmonella enterica Serovar Paratyphi A Confers Immunoprotection against Infection by Salmonella enterica Serovar Typhi. Front Cell Infect Microbiol 2017; 7:135. [PMID: 28484685 PMCID: PMC5401900 DOI: 10.3389/fcimb.2017.00135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/31/2017] [Indexed: 11/28/2022] Open
Abstract
Enteric fever is predominantly caused by Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A, and accounts for an annual global incidence of 26.9 millions. In recent years, the rate of S. Paratyphi A infection has progressively increased. Currently licensed vaccines for typhoid fever, live Ty21a vaccine, Vi subunit vaccine, and Vi-conjugate vaccine, confer inadequate cross immunoprotection against enteric fever caused by S. Paratyphi A. Therefore, development of bivalent vaccines against enteric fever is urgently required. The immunogenic Vi capsular polysaccharide is characteristically produced in S. Typhi, but it is absent in S. Paratyphi A. We propose that engineering synthesis of Vi in S. Paratyphi A live-attenuated vaccine may expand its protection range to cover S. Typhi. In this study, we cloned the viaB locus, which contains 10 genes responsible for Vi biosynthesis, and integrated into the chromosome of S. Paratyphi A CMCC 50093. Two virulence loci, htrA and phoPQ, were subsequently deleted to achieve a Vi-producing attenuated vaccine candidate. Our data showed that, despite more than 200 passages, the viaB locus was stably maintained in the chromosome of S. Paratyphi A and produced the Vi polysaccharide. Nasal immunization of the vaccine candidate stimulated high levels of Vi-specific and S. Paratyphi A-specific antibodies in mice sera as well as total sIgA in intestinal contents, and showed significant protection against wild-type challenge of S. Paratyphi A or S. Typhi. Our study show that the Vi-producing attenuated S. Paratyphi A is a promising bivalent vaccine candidate for the prevention of enteric fever.
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Affiliation(s)
- Kun Xiong
- Department of Microbiology, Third Military Medical UniversityChongqing, China
| | - Chunyue Zhu
- Outpatient Department of 95851 Unit of PLANanjing, China
| | - Zhijin Chen
- Department of Microbiology, Third Military Medical UniversityChongqing, China
| | - Chunping Zheng
- Department of Microbiology, Third Military Medical UniversityChongqing, China
| | - Yong Tan
- Department of Microbiology, Third Military Medical UniversityChongqing, China
| | - Xiancai Rao
- Department of Microbiology, Third Military Medical UniversityChongqing, China
| | - Yanguang Cong
- Department of Microbiology, Third Military Medical UniversityChongqing, China
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Gandhi GD, Krishnamoorthy N, Motal UMA, Yacoub M. Towards developing a vaccine for rheumatic heart disease. Glob Cardiol Sci Pract 2017; 2017:e201704. [PMID: 28971103 PMCID: PMC5621712 DOI: 10.21542/gcsp.2017.4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rheumatic heart disease (RHD) is the most serious manifestations of rheumatic fever, which is caused by group A Streptococcus (GAS or Streptococcus pyogenes) infection. RHD is an auto immune sequelae of GAS pharyngitis, rather than the direct bacterial infection of the heart, which leads to chronic heart valve damage. Although antibiotics like penicillin are effective against GAS infection, improper medical care such as poor patient compliance, overcrowding, poverty, and repeated exposure to GAS, leads to acute rheumatic fever and RHD. Thus, efforts have been put forth towards developing a vaccine. However, a potential global vaccine is yet to be identified due to the widespread diversity of S. pyogenes strains and cross reactivity of streptococcal proteins with host tissues. In this review, we discuss the available vaccine targets of S. pyogenes and the significance of in silico approaches in designing a vaccine for RHD.
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Affiliation(s)
- Geethanjali Devadoss Gandhi
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar
| | - Navaneethakrishnan Krishnamoorthy
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ussama M Abdel Motal
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar
| | - Magdi Yacoub
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Steele AD, Hay Burgess DC, Diaz Z, Carey ME, Zaidi AKM. Challenges and Opportunities for Typhoid Fever Control: A Call for Coordinated Action. Clin Infect Dis 2016; 62 Suppl 1:S4-8. [PMID: 26933019 PMCID: PMC4772836 DOI: 10.1093/cid/civ976] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The burden of enteric fever caused by Salmonella enterica serovars Typhi and Paratyphi is substantial and has high impact in toddlers and young children. This burden is relatively well documented in Asia, and this supplement provides new data on the substantial burden in several sub-Saharan African countries. Challenges in standardized surveillance and imperfect diagnostic tools have resulted in patchy local disease data, which are not well acknowledged or integrated into local country evidence and health awareness for decision making. There is a need to strengthen diagnostics for the generation of burden data in country. Furthermore, the guidelines and training for treatment of enteric fever cases in Africa are sorely needed to help mitigate the inappropriate use of antimicrobial treatment. Classic water safety and access to sanitation development remain powerful tools for the control of typhoid fever, yet the huge economic costs and long timelines are unlikely to provide a short- to middle-term solution. Emerging threats, including multidrug resistance and increasing urbanization in regions such as sub-Saharan Africa, warrant focused attention to shorter-term interventions including immunization, and must include vaccine strategies with the new typhoid conjugate vaccines.
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Affiliation(s)
- A Duncan Steele
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Deborah C Hay Burgess
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Zoey Diaz
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Megan E Carey
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Anita K M Zaidi
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
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Hu X, Chen Z, Xiong K, Wang J, Rao X, Cong Y. Vi capsular polysaccharide: Synthesis, virulence, and application. Crit Rev Microbiol 2016; 43:440-452. [PMID: 27869515 DOI: 10.1080/1040841x.2016.1249335] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Vi capsular polysaccharide, a linear homopolymer of α-1,4-linked N-acetylgalactosaminuronate, is characteristically produced by Salmonella enterica serovar Typhi. The Vi capsule covers the surface of the producing bacteria and serves as an virulence factor via inhibition of complement-mediated killing and promoting resistance against phagocytosis. Furthermore, Vi also represents a predominant protective antigen and plays a key role in the development of vaccines against typhoid fever. Herein, we reviewed the latest advances associated with the Vi polysaccharide, from its synthesis and transport within bacterial cells, mechanisms involved in virulence, immunological characteristics, and applications in vaccine, as well as its purification and detection methods.
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Affiliation(s)
- Xiaomei Hu
- a Department of Microbiology , Third Military Medical University , Chongqing , China
| | - Zhijin Chen
- a Department of Microbiology , Third Military Medical University , Chongqing , China
| | - Kun Xiong
- a Department of Microbiology , Third Military Medical University , Chongqing , China
| | - Jing Wang
- a Department of Microbiology , Third Military Medical University , Chongqing , China
| | - Xiancai Rao
- a Department of Microbiology , Third Military Medical University , Chongqing , China
| | - Yanguang Cong
- a Department of Microbiology , Third Military Medical University , Chongqing , China
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John J, Van Aart CJC, Grassly NC. The Burden of Typhoid and Paratyphoid in India: Systematic Review and Meta-analysis. PLoS Negl Trop Dis 2016; 10:e0004616. [PMID: 27082958 PMCID: PMC4833325 DOI: 10.1371/journal.pntd.0004616] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/17/2016] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Typhoid is an important public health challenge for India, especially with the spread of antimicrobial resistance. The decision about whether to introduce a public vaccination programme needs to be based on an understanding of disease burden and the age-groups and geographic areas at risk. METHODS We searched Medline and Web of Science databases for studies reporting the incidence or prevalence of typhoid and paratyphoid fever confirmed by culture and/or serology, conducted in India and published between 1950 and 2015. We used binomial and Poisson mixed-effects meta-regression models to estimate prevalence and incidence from hospital and community studies, and to identify risk-factors. RESULTS We identified 791 titles and abstracts, and included 37 studies of typhoid and 18 studies of paratyphoid in the systematic review and meta-analysis. The estimated prevalence of laboratory-confirmed typhoid and paratyphoid among individuals with fever across all hospital studies was 9.7% (95% CI: 5.7-16.0%) and 0.9% (0.5-1.7%) respectively. There was significant heterogeneity among studies (p-values<0.001). Typhoid was more likely to be detected among clinically suspected cases or during outbreaks and showed a significant decline in prevalence over time (odds ratio for each yearly increase in study date was 0.96 (0.92-0.99) in the multivariate meta-regression model). Paratyphoid did not show any trend over time and there was no clear association with risk-factors. Incidence of typhoid and paratyphoid was reported in 3 and 2 community cohort studies respectively (in Kolkata and Delhi, or Kolkata alone). Pooled estimates of incidence were 377 (178-801) and 105 (74-148) per 100,000 person years respectively, with significant heterogeneity between locations for typhoid (p<0.001). Children 2-4 years old had the highest incidence. CONCLUSIONS Typhoid remains a significant burden in India, particularly among young children, despite apparent declines in prevalence. Infant immunisation with newly-licensed conjugate vaccines could address this challenge.
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Affiliation(s)
- Jacob John
- Department of Community Health, Christian Medical College, Vellore, India
| | - Carola J. C. Van Aart
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Nicholas C. Grassly
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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Mogasale V, Maskery B, Ochiai RL, Lee JS, Mogasale VV, Ramani E, Kim YE, Park JK, Wierzba TF. Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment. LANCET GLOBAL HEALTH 2015; 2:e570-80. [PMID: 25304633 DOI: 10.1016/s2214-109x(14)70301-8] [Citation(s) in RCA: 336] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income and middle-income countries (LMICs) after adjusting for water-related risk. METHODS We estimated the typhoid disease burden from studies done in LMICs based on blood-culture-confirmed incidence rates applied to the 2010 population, after correcting for operational issues related to surveillance, limitations of diagnostic tests, and water-related risk. We derived incidence estimates, correction factors, and mortality estimates from systematic literature reviews. We did scenario analyses for risk factors, diagnostic sensitivity, and case fatality rates, accounting for the uncertainty in these estimates and we compared them with previous disease burden estimates. FINDINGS The estimated number of typhoid fever cases in LMICs in 2010 after adjusting for water-related risk was 11·9 million (95% CI 9·9-14·7) cases with 129 000 (75 000-208 000) deaths. By comparison, the estimated risk-unadjusted burden was 20·6 million (17·5-24·2) cases and 223 000 (131 000-344 000) deaths. Scenario analyses indicated that the risk-factor adjustment and updated diagnostic test correction factor derived from systematic literature reviews were the drivers of differences between the current estimate and past estimates. INTERPRETATION The risk-adjusted typhoid fever burden estimate was more conservative than previous estimates. However, by distinguishing the risk differences, it will allow assessment of the effect at the population level and will facilitate cost-effectiveness calculations for risk-based vaccination strategies for future typhoid conjugate vaccine.
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Affiliation(s)
| | | | | | | | | | - Enusa Ramani
- International Vaccine Institute, Seoul, South Korea
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Miyazu M, Kikuchi H, Hamada A, Fukushima S, Ouchi K, Bosch Castells V, Mihara H, Bonnet MC. A Japanese study to assess immunogenicity and safety of a typhoid Vi polysaccharide vaccine. Vaccine 2015; 33:6697-702. [DOI: 10.1016/j.vaccine.2015.10.086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/28/2015] [Accepted: 10/17/2015] [Indexed: 11/26/2022]
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Kinnear CL, Strugnell RA. Vaccination Method Affects Immune Response and Bacterial Growth but Not Protection in the Salmonella Typhimurium Animal Model of Typhoid. PLoS One 2015; 10:e0141356. [PMID: 26509599 PMCID: PMC4625024 DOI: 10.1371/journal.pone.0141356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 10/07/2015] [Indexed: 01/22/2023] Open
Abstract
Understanding immune responses elicited by vaccines, together with immune responses required for protection, is fundamental to designing effective vaccines and immunisation programs. This study examines the effects of the route of administration of a live attenuated vaccine on its interactions with, and stimulation of, the murine immune system as well as its ability to increase survival and provide protection from colonisation by a virulent challenge strain. We assess the effect of administration method using the murine model for typhoid, where animals are infected with S. Typhimurium. Mice were vaccinated either intravenously or orally with the same live attenuated S. Typhimurium strain and data were collected on vaccine strain growth, shedding and stimulation of antibodies and cytokines. Following vaccination, mice were challenged with a virulent strain of S. Typhimurium and the protection conferred by the different vaccination routes was measured in terms of challenge suppression and animal survival. The main difference in immune stimulation found in this study was the development of a secretory IgA response in orally-vaccinated mice, which was absent in IV vaccinated mice. While both strains showed similar protection in terms of challenge suppression in systemic organs (spleen and liver) as well as survival, they differed in terms of challenge suppression of virulent pathogens in gut-associated organs. This difference in gut colonisation presents important questions around the ability of vaccines to prevent shedding and transmission. These findings demonstrate that while protection conferred by two vaccines can appear to be the same, the mechanisms controlling the protection can differ and have important implications for infection dynamics within a population.
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Affiliation(s)
- Clare L. Kinnear
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
| | - Richard A. Strugnell
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
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Roggelin L, Vinnemeier CD, Fischer-Herr J, Johnson-Weaver BT, Rolling T, Burchard GD, Staats HF, Cramer JP. Serological response following re-vaccination with Salmonella typhi Vi-capsular polysaccharide vaccines in healthy adult travellers. Vaccine 2015; 33:4141-5. [DOI: 10.1016/j.vaccine.2015.05.080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 11/25/2022]
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Abstract
Efficacious typhoid fever vaccines have been available for decades. Typhoid fever burden of disease estimates indicate a substantial burden of illness and death in low-resource areas. The World Health Organization has recommended that countries consider the use of typhoid vaccines for high-risk groups and populations, and for outbreak control. Despite this, typhoid vaccines are not widely used in endemic areas. By examining strategies to improve burden of disease data, use of transmission dynamic models, economic evaluations, vaccine strategies, and experiences with typhoid vaccine pilot projects, the papers in this supplement help to plot the path toward rational and wider use of typhoid vaccines.
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Affiliation(s)
- John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand.
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46
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Chinnasami B, Sadasivam K, Vivekanandhan A, Arunachalam P, Pasupathy S. A Study on Longevity of Immune Response after Vaccination with Salmonella Typhi Vi Conjugate Vaccine (Pedatyph™) in Children. J Clin Diagn Res 2015; 9:SC01-3. [PMID: 26155525 DOI: 10.7860/jcdr/2015/13302.5903] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/05/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Owing to the limitations of the conventional polysaccharide vaccines, global efforts have been made to develop conjugated polysaccharide vaccines for typhoid. Duration of immune response induced by these vaccines is critical to define the efficacy and frequency of required booster dose. This study was done to determine the duration of immune response following vaccination with Salmonella Typhi Vi conjugate vaccine (Pedatyph™) in children and to assess the booster effect of second dose of conjugate typhoid vaccine. MATERIALS AND METHODS Forty children were recalled from a cohort of 400 children, who received one dose or two doses of PedaTyph™, 30 months after vaccination. Ten non-vaccinated children were also recalled. Their serum samples were assessed by ELISA for anti Vi antibody. RESULTS Significantly high titers of anti-Vi polysaccharide IgG antibodies were present in vaccinated children even after 30 months of vaccination as compared to non-vaccinated children. Geometric mean titers (GMT) with 95% confidence intervals were 14 (4.8-29.8), 17 (7.4-33) and 6.4 (0.8-12) μg/ml for single dose, two doses and control group respectively. The children in two doses group had higher antibody titers as compared to single dose group. However, the difference was not significant. INTERPRETATION AND CONCLUSION PedaTyph™ was found to induce long term immune response as evidenced by presence of significant anti-Vi polysaccharide antibodies after 30 months of vaccination. No significant advantage of two doses regimen over one dose was found. Hence one dose vaccination with PedaTyph™ is suggested.
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Affiliation(s)
- Balaji Chinnasami
- Associate Professor, Department of Paediatrics, SRM MCH& RC , Chennai, India
| | | | - Aravindhan Vivekanandhan
- Researcher, Department of Immunology and Molecular Biology, AU-KBC Research Centre, MIT Campus of Anna University , Chrompet, Chennai, India
| | - Prema Arunachalam
- Former, Professor & HOD, Department of Paediatrics, SRM MCH& RC , Chennai, India
| | - Sekar Pasupathy
- Professor & HOD, Department of Paediatrics, SRM MCH& RC , Chennai, India
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Mohan VK, Varanasi V, Singh A, Pasetti MF, Levine MM, Venkatesan R, Ella KM. Safety and immunogenicity of a Vi polysaccharide-tetanus toxoid conjugate vaccine (Typbar-TCV) in healthy infants, children, and adults in typhoid endemic areas: a multicenter, 2-cohort, open-label, double-blind, randomized controlled phase 3 study. Clin Infect Dis 2015; 61:393-402. [PMID: 25870324 DOI: 10.1093/cid/civ295] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/04/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Enteric fever caused by Salmonella Typhi remains a major public health problem in developing countries. Typbar-TCV is a single-dose typhoid Vi polysaccharide-tetanus toxoid conjugate vaccine for persons ≥6 months of age. METHODS Six hundred fifty-four healthy subjects aged 2-45 years enrolled in a double-blind, randomized controlled trial (RCT) received a single dose of Typbar-TCV or comparator "Vi polysaccharide" (Typbar), and 327 healthy subjects aged 6-23 months received a single dose of Typbar-TCV in an open-label trial (OLT); both received single- or multidose presentations from different lots. After 2 years, subsets in each group received a booster dose. The primary objective included analysis of geometric mean titer (GMTs) and 4-fold rise of anti-Vi serum immunoglobulin G (IgG) enzyme-linked immunosorbent assay titers over baseline (seroconversion [SCN]) 42 days after immunization. RESULTS Typbar-TCV recipients in the RCT attained higher anti-Vi IgG GMTs 42 days after immunization (SCN, 97%; GMT, 1293 [95% confidence interval {CI}, 1153-1449]) than recipients of Typbar (SCN, 93%; GMT, 411 [95% CI, 359-471]) (P < .001). Typbar-TCV was highly immunogenic in the OLT (SCN, 98%; GMT, 1937 [95% CI, 1785-2103]). Two years after vaccination, anti-Vi titers remained higher in Typbar-TCV subjects (GMT, 82 [95% CI, 73-92]); and exhibited higher avidity (geometric mean avidity index [GMAI], 60%) than in Typbar recipients (GMT, 46 [95% CI, 40-53]; GMAI 46%) in the RCT (P < .001). OLT Typbar-TCV recipients achieved GMT of 48 (95% CI, 42-55) and GMAI of 57%. Typbar-TCV induced multiple IgG subclasses and strong booster responses in all ages. No serious vaccine-attributable adverse events were observed. CONCLUSIONS Single-dose Typbar-TCV is well tolerated and induces robust and long-lasting serum anti-Vi IgG across age groups. CLINICAL TRIALS REGISTRATION CTRI/2011/08/001957, CTRI/2014/01/004341.
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Affiliation(s)
| | - Vineeth Varanasi
- Bharat Biotech International Limited, Hyderabad, Telangana, India
| | - Anit Singh
- Bharat Biotech International Limited, Hyderabad, Telangana, India
| | - Marcela F Pasetti
- Centre for Vaccine Development, University of Maryland School of Medicine, Baltimore
| | - Myron M Levine
- Centre for Vaccine Development, University of Maryland School of Medicine, Baltimore
| | | | - Krishna M Ella
- Bharat Biotech International Limited, Hyderabad, Telangana, India
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MacLennan CA, Martin LB, Micoli F. Vaccines against invasive Salmonella disease: current status and future directions. Hum Vaccin Immunother 2014; 10:1478-93. [PMID: 24804797 PMCID: PMC4185946 DOI: 10.4161/hv.29054] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field.
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Affiliation(s)
- Calman A MacLennan
- Novartis Vaccines Institute for Global Health; Siena, Italy; Medical Research Council Centre for Immune Regulation and Clinical Immunology Service; Institute of Biomedical Research, School of Immunity and Infection; College of Medicine and Dental Sciences; University of Birmingham; Birmingham, UK
| | - Laura B Martin
- Novartis Vaccines Institute for Global Health; Siena, Italy
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Szu SC, Klugman KP, Hunt S. Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children. Vaccine 2014; 32:2359-63. [PMID: 24630869 DOI: 10.1016/j.vaccine.2014.02.050] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 02/05/2014] [Accepted: 02/12/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a "protective level" of serum antibodies to Vi antigen. METHODS The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. RESULTS Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0μg/ml (short term threshold). When applying a protective threshold of 10μg/ml at 6 months post immunization, an IgG level in excess of 1.4μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG>10μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. CONCLUSION The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines.
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Affiliation(s)
- Shousun C Szu
- National Institute of Child Health & Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Keith P Klugman
- Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Steven Hunt
- National Institute of Child Health & Human Development, National Institutes of Health, Bethesda, MD, USA
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