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Martin LB, Tack B, Marchello CS, Sikorski MJ, Owusu-Dabo E, Nyirenda T, Mogasale V, Crump JA. Vaccine value profile for invasive non-typhoidal Salmonella disease. Vaccine 2024; 42:S101-S124. [PMID: 39003017 DOI: 10.1016/j.vaccine.2024.04.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 07/15/2024]
Abstract
Invasive non-typhoidal Salmonella (iNTS) disease is an under-recognized high-burden disease causing major health and socioeconomic issues in sub-Saharan Africa (sSA), predominantly among immune-naïve infants and young children, including those with recognized comorbidities such as HIV infection. iNTS disease is primarily caused by Salmonella enterica serovar Typhimurium sequence type (ST) 313 and 'African-restricted clades' of Salmonella Enteritidis ST11 that have emerged across the African continent as a series of epidemics associated with acquisition of new antimicrobial resistance. Due to genotypes with a high prevalence of antimicrobial resistance and scarcity of therapeutic options, these NTS serovars are designated by the World Health Organization as a priority pathogen for research and development of interventions, including vaccines, to address and reduce NTS associated bacteremia and meningitis in sSA. Novel and traditional vaccine technologies are being applied to develop vaccines against iNTS disease, and the results of the first clinical trials in the infant target population should become available in the near future. The "Vaccine Value Profile" (VVP) addresses information related predominantly to invasive disease caused by Salmonella Enteritidis and Salmonella Typhimurium prevalent in sSA. Information is included on stand-alone iNTS disease candidate vaccines and candidate vaccines targeting iNTS disease combined with another invasive serotype, Salmonella Typhi, that is also common across sSA. Out of scope for the first version of this VVP is a wider discussion on either diarrheagenic NTS disease (dNTS) also associated with Salmonella Enteritidis and Salmonella Typhimurium or the development of a multivalent Salmonella vaccines targeting key serovars for use globally. This VVP for vaccines to prevent iNTS disease is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic, and societal value of pipeline vaccines and vaccine-like products. Future versions of this VVP will be updated to reflect ongoing activities such as vaccine development strategies and a "Full Vaccine Value Assessment" that will inform the value proposition of an iNTS disease vaccine. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships, and multi-lateral organizations, and in collaboration with stakeholders from the World Health Organization African Region. All contributors have extensive expertise on various elements of the iNTS disease VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.
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Affiliation(s)
| | - Bieke Tack
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Belgium and Department of Microbiology, Immunology and Transplantation, KU Leuven, Belgium.
| | | | - Michael J Sikorski
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| | | | | | | | - John A Crump
- Centre for International Health, University of Otago, New Zealand.
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Gebreyesus TD, Makonnen E, Tadele T, Mekete K, Gashaw H, Gerba H, Aklillu E. Reduced efficacy of single-dose albendazole against Ascaris lumbricoides, and Trichuris trichiura, and high reinfection rate after cure among school children in southern Ethiopia: a prospective cohort study. Infect Dis Poverty 2024; 13:8. [PMID: 38246985 PMCID: PMC10802031 DOI: 10.1186/s40249-024-01176-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Mass drug administration (MDA) program of albendazole to at-risk populations as preventive chemotherapy is the core public health intervention to control soil-transmitted helminths (STHs). Achieving this goal relies on drug effectiveness in reducing the parasite reservoirs in the community and preventing reinfection. We assessed the efficacy of albendazole against STH parasite infection and reinfection status after cure. METHODS A total of 984 schoolchildren infected with at least one type of STH parasite (hookworm, Ascaris lumbricoides, Trichuris trichiura) in southern Ethiopia were enrolled and received albendazole and praziquantel in MDA campaign conducted from January to March 2019. Stool exams at week-4 and at week-8 of post-MDA were done using Kato Katz technique. The primary outcome was efficacy assessed by cure rate (CR) and fecal egg reduction rates (ERRs) at four weeks of post-MDA. The secondary outcome was reinfection status defined as parasite egg positivity at eight weeks among those who were cured at 4 weeks of post-MDA. Group comparisons in CR and related factors were assessed with chi-square or Fisher's exact tests. Predictors of CR were examined through univariate and multivariate regression analyses. RESULTS The overall CR and ERR for hookworm infection were 97.2% (95% CI 94.6-99.4) and 97.02%, respectively. The overall CR and ERR for A. lumbricoides were 71.5% (95% CI 68.3-74.6) and 84.5% respectively. The overall CR and ERR and for T. trichiura were 49.5% (95% CI 44.8-54.2) and 68.3%, respectively. The CR among moderate T. trichiura infection intensity was 28.6%. Among children cured of hookworm, A. lumbricoides and T. trichiura at week 4 post-MDA, 4.6%, 18.3% and 52.4% became reinfected at week-8 post-MDA, respectively. Significantly lower CR (36.6%) and higher reinfection after cure (60.6%) among A. lumbricoides and T. trichiura coinfected children than A. lumbricoides only (CR = 69.6%, reinfection rate = 15.1%) or T. trichiura only infected children (CR = 55.6%, reinfection rate = 47.1%) was observed. Pre-treatment coinfection with ≥ two types of STH parasites was significantly associated with re-infection after cure. CONCLUSION Albendazole MDA is efficacious against hookworm but has reduced efficacy against A. lumbricoides and is not effective against T. trichiura. The low drug efficacy and high reinfection rate after cure underscore the need for alternative treatment and integration of other preventive measures to achieve the target of eliminating STHs as a public health problem by 2030.
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Affiliation(s)
- Tigist Dires Gebreyesus
- Department of Global Public Health, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Ethiopian Food and Drug Authority, Addis Ababa, Ethiopia
| | - Eyasu Makonnen
- Center for Innovative Drug Development and Therapeutic Trials for Africa, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
- Departments of Pharmacology and Clinical Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Tafesse Tadele
- College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
| | | | - Habtamu Gashaw
- Ethiopian Food and Drug Authority, Addis Ababa, Ethiopia
| | - Heran Gerba
- Ethiopian Food and Drug Authority, Addis Ababa, Ethiopia
| | - Eleni Aklillu
- Department of Global Public Health, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
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Tadesse BT, Keddy KH, Rickett NY, Zhusupbekova A, Poudyal N, Lawley T, Osman M, Dougan G, Kim JH, Lee JS, Jeon HJ, Marks F. Vaccination to Reduce Antimicrobial Resistance Burden-Data Gaps and Future Research. Clin Infect Dis 2023; 77:S597-S607. [PMID: 38118013 PMCID: PMC10732565 DOI: 10.1093/cid/ciad562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023] Open
Abstract
Antimicrobial resistance (AMR) poses an immediate danger to global health. If unaddressed, the current upsurge in AMR threatens to reverse the achievements in reducing the infectious disease-associated mortality and morbidity associated with antimicrobial treatment. Consequently, there is an urgent need for strategies to prevent or slow the progress of AMR. Vaccines potentially contribute both directly and indirectly to combating AMR. Modeling studies have indicated significant gains from vaccination in reducing AMR burdens for specific pathogens, reducing mortality/morbidity, and economic loss. However, quantifying the real impact of vaccines in these reductions is challenging because many of the study designs used to evaluate the contribution of vaccination programs are affected by significant background confounding, and potential selection and information bias. Here, we discuss challenges in assessing vaccine impact to reduce AMR burdens and suggest potential approaches for vaccine impact evaluation nested in vaccine trials.
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Affiliation(s)
- Birkneh Tilahun Tadesse
- International Vaccine Institute, Seoul, Republic of Korea
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
- Center for Innovative Drug Development and Therapeutic Trials for Africa, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | | | - Nimesh Poudyal
- International Vaccine Institute, Seoul, Republic of Korea
| | - Trevor Lawley
- Wellcome Sanger Institute and Microbiotica, Cambridge, United Kingdom
| | - Majdi Osman
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Gordon Dougan
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
- Seoul National University, College of Natural Sciences, Seoul, Republic of Korea
| | - Jung-Seok Lee
- International Vaccine Institute, Seoul, Republic of Korea
| | - Hyon Jin Jeon
- International Vaccine Institute, Seoul, Republic of Korea
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- Madagascar Institute for Vaccine Research, University of Antananarivo, Antananarivo, Madagascar
| | - Florian Marks
- International Vaccine Institute, Seoul, Republic of Korea
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- Madagascar Institute for Vaccine Research, University of Antananarivo, Antananarivo, Madagascar
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
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4
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Batool R, Yousafzai MT, Qureshi S, Muhammad S, Qazi I, Sadaf T, Ashorn P, Qamar FN. Parental acceptance of typhoid conjugate vaccine for children aged 6 months to 15 years in an outbreak setting of Lyari Town Karachi, Pakistan. Vaccine 2023; 41:5376-5382. [PMID: 37463829 PMCID: PMC10448379 DOI: 10.1016/j.vaccine.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/18/2023] [Accepted: 07/02/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND This study aimed to evaluate the parental acceptance of Typhoid Conjugate Vaccine (TCV) and to determine the predictors of TCV vaccination status among children in an outbreak setting of extensively drug resistant (XDR) typhoid fever in Karachi, Pakistan. METHODS A cross-sectional survey using the WHO recommended rapid vaccine coverage assessment technique was conducted. Out of 11, four union councils (UCs) in Lyari Town were randomly selected. A parent or primary caretaker from the eligible household was interviewed. Data were collected using a locally validated vaccine attitudes scale (VAS). Sum of scores was calculated for VAS. A higher score denoted negative attitudes and perceptions regarding TCV and vice versa. Multivariable logistic regression was performed to determine the predictors of TCV vaccination status. RESULTS Based on the 14-item parental VAS, 78.0 % of the parents had a score between 0 to <40 and 22 % had a score ≥40. VAS score of <40 was significantly associated with higher odds of receiving TCV during the campaign setting (adjusted Odds Ratio (aOR): 1.30; 95 % Confidence Interval (CI): 1.02, 1.66). The odds of receiving TCV vaccination were higher among children whose parents were aware of the ongoing vaccination campaign in the area (aOR: 4.57; 95 % CI: 2.93, 7.12) and expressed willingness to get their child vaccinated against typhoid fever (aOR: 2.54; 95 % CI: 1.82, 3.55). CONCLUSION Parental awareness of the ongoing vaccination campaign, positive perception and attitudes towards vaccine were found to be significantly associated with TCV vaccination among children. Appropriately structured pre-vaccination awareness campaigns focused on childhood vaccination targeted towards parents are necessary to improve parental awareness, attitude and behavior towards vaccination.
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Affiliation(s)
- Rabab Batool
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan; Centre for Child, Adolescent, and Maternal Health Research, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Tampere 33520, Finland
| | - Mohammad Tahir Yousafzai
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan; The Kirby Institute, UNSW Sydney, Wallace Wurth Building High Street, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Sonia Qureshi
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan
| | - Sajid Muhammad
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan
| | - Ibtisam Qazi
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan
| | - Tahira Sadaf
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan
| | - Per Ashorn
- Centre for Child, Adolescent, and Maternal Health Research, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Tampere 33520, Finland
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500 Karachi 74800, Pakistan.
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Nampota-Nkomba N, Carey ME, Jamka LP, Fecteau N, Neuzil KM. Using Typhoid Conjugate Vaccines to Prevent Disease, Promote Health Equity, and Counter Drug-Resistant Typhoid Fever. Open Forum Infect Dis 2023; 10:S6-S12. [PMID: 37274532 PMCID: PMC10236511 DOI: 10.1093/ofid/ofad022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Typhoid fever is a serious disease that disproportionately impacts children in low-resource settings in sub-Saharan Africa, South and Southeast Asia, and the Western Pacific. The prevalence of antimicrobial-resistant strains of S. Typhi continue to increase worldwide. Two safe, effective, and cost-effective typhoid conjugate vaccines (TCVs) are World Health Organization-prequalified for the prevention of typhoid fever in children as young as 6 months. Typhoid conjugate vaccines have proven effectiveness in preventing drug-resistant S. Typhi and have been deployed successfully in outbreak response and routine immunization scenarios. Broad and equitable distribution of TCVs is essential to combat the spread and potentially devastating consequences of typhoid fever. It is vital to empower decision-makers in typhoid-endemic countries to introduce TCVs and for leaders to embrace this critical tool to prevent typhoid fever, slow the spread of drug-resistant S. Typhi strains, promote health equity, and save lives.
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Affiliation(s)
| | - Megan E Carey
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Leslie P Jamka
- Correspondence: Leslie Jamka, MEM, MS, 685 W. Baltimore Street, #480, Baltimore, MD 21201, USA (). Kathleen Neuzil, 685 W. Baltimore Street, #480 Baltimore, MD 21201, USA ()
| | - Natalie Fecteau
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kathleen M Neuzil
- Correspondence: Leslie Jamka, MEM, MS, 685 W. Baltimore Street, #480, Baltimore, MD 21201, USA (). Kathleen Neuzil, 685 W. Baltimore Street, #480 Baltimore, MD 21201, USA ()
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Helmy YA, Taha-Abdelaziz K, Hawwas HAEH, Ghosh S, AlKafaas SS, Moawad MMM, Saied EM, Kassem II, Mawad AMM. Antimicrobial Resistance and Recent Alternatives to Antibiotics for the Control of Bacterial Pathogens with an Emphasis on Foodborne Pathogens. Antibiotics (Basel) 2023; 12:274. [PMID: 36830185 PMCID: PMC9952301 DOI: 10.3390/antibiotics12020274] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/21/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Antimicrobial resistance (AMR) is one of the most important global public health problems. The imprudent use of antibiotics in humans and animals has resulted in the emergence of antibiotic-resistant bacteria. The dissemination of these strains and their resistant determinants could endanger antibiotic efficacy. Therefore, there is an urgent need to identify and develop novel strategies to combat antibiotic resistance. This review provides insights into the evolution and the mechanisms of AMR. Additionally, it discusses alternative approaches that might be used to control AMR, including probiotics, prebiotics, antimicrobial peptides, small molecules, organic acids, essential oils, bacteriophage, fecal transplants, and nanoparticles.
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Affiliation(s)
- Yosra A. Helmy
- Department of Veterinary Science, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY 40546, USA
- Department of Zoonoses, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Khaled Taha-Abdelaziz
- Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634, USA
| | - Hanan Abd El-Halim Hawwas
- Department of Zoonoses, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9301, South Africa
| | - Samar Sami AlKafaas
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta 31511, Egypt
| | | | - Essa M. Saied
- Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt
- Institute for Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Issmat I. Kassem
- Centre for Food Safety, Department of Food Science and Technology, University of Georgia, Griffin, GA 30609, USA
| | - Asmaa M. M. Mawad
- Department of Biology, College of Science, Taibah University, Madinah 42317, Saudi Arabia
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
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7
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Doyle SR, Søe MJ, Nejsum P, Betson M, Cooper PJ, Peng L, Zhu XQ, Sanchez A, Matamoros G, Sandoval GAF, Cutillas C, Tchuenté LAT, Mekonnen Z, Ame SM, Namwanje H, Levecke B, Berriman M, Fredensborg BL, Kapel CMO. Population genomics of ancient and modern Trichuris trichiura. Nat Commun 2022; 13:3888. [PMID: 35794092 PMCID: PMC9259628 DOI: 10.1038/s41467-022-31487-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 06/17/2022] [Indexed: 11/14/2022] Open
Abstract
The neglected tropical disease trichuriasis is caused by the whipworm Trichuris trichiura, a soil-transmitted helminth that has infected humans for millennia. Today, T. trichiura infects as many as 500 million people, predominantly in communities with poor sanitary infrastructure enabling sustained faecal-oral transmission. Using whole-genome sequencing of geographically distributed worms collected from human and other primate hosts, together with ancient samples preserved in archaeologically-defined latrines and deposits dated up to one thousand years old, we present the first population genomics study of T. trichiura. We describe the continent-scale genetic structure between whipworms infecting humans and baboons relative to those infecting other primates. Admixture and population demographic analyses support a stepwise distribution of genetic variation that is highest in Uganda, consistent with an African origin and subsequent translocation with human migration. Finally, genome-wide analyses between human samples and between human and non-human primate samples reveal local regions of genetic differentiation between geographically distinct populations. These data provide insight into zoonotic reservoirs of human-infective T. trichiura and will support future efforts toward the implementation of genomic epidemiology of this globally important helminth.
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Affiliation(s)
| | - Martin Jensen Søe
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Peter Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
| | - Martha Betson
- School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Philip J Cooper
- Institute of Infection and Immunity, St George's University of London, London, UK
- School of Medicine, Universidad Internacional del Ecuador, Quito, Ecuador
| | - Lifei Peng
- Department of Parasitology, School of Basic Medical Sciences, Guangdong Medical University, Zhanjiang, Guangdong Province, People's Republic of China
| | - Xing-Quan Zhu
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, People's Republic of China
| | - Ana Sanchez
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Gabriela Matamoros
- Microbiology Research Institute, Ciudad Universitaria, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | | | - Cristina Cutillas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain
| | | | - Zeleke Mekonnen
- Institute of Health, School of Medical Laboratory Sciences, Jimma University, Jimma, Ethiopia
| | - Shaali M Ame
- Public Health Laboratory Ivo de Carneri, Pemba, Tanzania
| | | | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Ghent, Belgium
| | | | - Brian Lund Fredensborg
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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IRENA TSEGAYEKEBEDE, GAKKHAR SUNITA. MODELING THE ROLE OF VACCINATION, ENVIRONMENTAL SANITATION, AND SATURATED TREATMENT ON THE SPREAD OF TYPHOID FEVER. J BIOL SYST 2022. [DOI: 10.1142/s0218339022500164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A deterministic nonlinear mathematical model is developed for typhoid transmission dynamics in human hosts, coupled with multiple transmission routes. The model aims to examine the role of control interventions such as vaccination, environmental sanitation, and saturated treatment on the prevalence of typhoid. First, the qualitative analysis of the model with constant control interventions is performed. The model exhibits a backward bifurcation phenomenon. Sensitivity analysis is also conducted to identify impactful parameters for effective control of the disease. Then, the model is extended to a corresponding optimal control problem to investigate the optimum intervention strategies by assessing their effects on typhoid prevalence and economic load. The characterization of the optimal controls is determined using Pontryagin’s Maximum Principle, and the optimality system is developed. Numerical results suggest that, in the absence of treatment, the combination of vaccination and environmental sanitation controls plays an important role in reducing the typhoid burden and economic load. Moreover, the comprehensive use of the three control interventions is more effective than using any single or two combined control interventions. It reduces the number of infective humans and environmental bacteria as well as the cost burden associated with applied controls and opportunity loss. Thus, the comprehensive effect of the three control interventions is found to be more economical during typhoid outbreaks.
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Affiliation(s)
- TSEGAYE KEBEDE IRENA
- Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - SUNITA GAKKHAR
- Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
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9
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Birger R, Antillón M, Bilcke J, Dolecek C, Dougan G, Pollard AJ, Neuzil KM, Frost I, Laxminarayan R, Pitzer VE. Estimating the effect of vaccination on antimicrobial-resistant typhoid fever in 73 countries supported by Gavi: a mathematical modelling study. THE LANCET INFECTIOUS DISEASES 2022; 22:679-691. [PMID: 35123673 PMCID: PMC9021026 DOI: 10.1016/s1473-3099(21)00627-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/20/2021] [Accepted: 09/23/2021] [Indexed: 11/24/2022]
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10
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Vekemans J, Hasso-Agopsowicz M, Kang G, Hausdorff WP, Fiore A, Tayler E, Klemm EJ, Laxminarayan R, Srikantiah P, Friede M, Lipsitch M. Leveraging Vaccines to Reduce Antibiotic Use and Prevent Antimicrobial Resistance: A World Health Organization Action Framework. Clin Infect Dis 2021; 73:e1011-e1017. [PMID: 33493317 PMCID: PMC8366823 DOI: 10.1093/cid/ciab062] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/21/2021] [Indexed: 11/17/2022] Open
Abstract
This Action Framework identifies priority actions to prevent antimicrobial-resistant (AMR) through expanding the use of licensed vaccines, developing new vaccines that contribute to the prevention and control of AMR, and expanding knowledge about the impact of vaccines on AMR.
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Affiliation(s)
- Johan Vekemans
- Immunization, Vaccines and Biologicals (IVB), World Health Organization (WHO), Geneva, Switzerland
| | - Mateusz Hasso-Agopsowicz
- Immunization, Vaccines and Biologicals (IVB), World Health Organization (WHO), Geneva, Switzerland
| | - Gagandeep Kang
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore TN, India
| | - William P Hausdorff
- PATH, Washington, District of Columbia, USA Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Anthony Fiore
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Elizabeth Tayler
- Antimicrobial Resistance Division, World Health Organization (WHO), Geneva, Switzerland
| | | | - Ramanan Laxminarayan
- Center for Disease Dynamics, Economics & Policy, Washington District of Columbia, USA
| | | | - Martin Friede
- Immunization, Vaccines and Biologicals (IVB), World Health Organization (WHO), Geneva, Switzerland
| | - Marc Lipsitch
- Harvard T. H. Chang School of Public Medicine, Boston, Massachusetts, USA
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11
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Chauhan AS, Kapoor I, Rana SK, Kumar D, Gupta M, John J, Kang G, Prinja S. Cost effectiveness of typhoid vaccination in India. Vaccine 2021; 39:4089-4098. [PMID: 34120765 PMCID: PMC8256879 DOI: 10.1016/j.vaccine.2021.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 11/09/2022]
Abstract
INTRODUCTION World Health Organization has prequalified the use of typhoid conjugate vaccine (TCV) in children over six months of age in typhoid endemic countries. We assessed the cost-effectiveness of introducing TCV separately for urban and rural areas of India. METHODS A decision analytic model was developed, using a societal perspective, to compare long-term costs and outcomes (3% discount rate) in a new-born cohort of 100,000 children immunized with or without TCV. Three vaccination scenarios were modelled, assuming the protective efficacy of TCV to last for 5, 10 and 15 years following immunization. Incidence of typhoid infection estimated under 'National Surveillance System for Enteric Fever' (NSSEFI)' was used. The prices of vaccine and cost of service delivery were included for vaccination arm. Both health system cost and out-of-pocket expenditures for treatment of typhoid illness and its complications was included. RESULTS TCV introduction in urban areas would result in prevention of 17% to 36% typhoid cases and deaths. With exclusion of indirect costs, the incremental cost per QALY gained was ₹ 151,346 (54,730-307,975), ₹ 61,710 (-5250 to 163,283) and ₹ 45,188 (-17,069 to 141,093) for scenario 1, 2 and 3 respectively. While, with inclusion of indirect costs, all 3 scenarios were cost saving. Further, in rural areas, TCV is estimated to reduce the typhoid cases and deaths by 19% to 36%, with ICER (incremental cost per QALY gained) ranging from ₹ 2340 (1316-4370) to ₹ 3574 (2057 - 6691) thousand (inclusive of indirect costs) among the 3 vaccination scenarios. CONCLUSION From a societal perspective, introduction of TCV is a cost saving strategy in urban India. Further, due to low incidence of typhoid infection, introduction of TCV is not cost-effective in rural settings of India.
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Affiliation(s)
- Akashdeep Singh Chauhan
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Isha Kapoor
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Saroj Kumar Rana
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Dilesh Kumar
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore 632 004, India
| | - Madhu Gupta
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Jacob John
- Department of Community Health, Christian Medical College, Vellore 632 002, India
| | - Gagandeep Kang
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore 632 004, India
| | - Shankar Prinja
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
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12
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Campillo JT, Awaca-Uvon NP, Tambwe JP, Kuyangisa-Simuna G, Vlaminck J, Weil GJ, Boussinesq M, Chesnais CB, Pion SDS. A strong effect of individual compliance with mass drug administration for lymphatic filariasis on sustained clearance of soil-transmitted helminth infections. Parasit Vectors 2021; 14:310. [PMID: 34103096 PMCID: PMC8186172 DOI: 10.1186/s13071-021-04814-2] [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: 02/20/2021] [Accepted: 05/28/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impact of semiannual mass drug administration (MDA) with albendazole (ALB; 400 mg) alone on lymphatic filariasis (LF) and soil-transmitted helminth (STH) infections was assessed during two trials conducted from 2012 to 2018 in the Republic of Congo and the Democratic Republic of Congo. The collected data were analyzed to evaluate the effect of compliance with ALB treatment on STH infections. METHODS STH infections were diagnosed with duplicate Kato-Katz thick smears and the results are reported as eggs per gram of stool. All subjects with at least two STH infection assessments were included in the analyses. We used parametric survival models to assess the influence of compliance with ALB treatment on the probability of (i) achieving sustained clearance of an STH infection, and (ii) acquiring an STH infection during the follow-up. RESULTS Out of 2658 subjects included in the trials, data on 202 participants (701 person-years; PY) with hookworm infection, 211 (651 PY) with Ascaris lumbricoides infection and 270 (1013 PY) with Trichuris trichiura infection were available to calculate the probability of achieving sustained clearance of infection. The effect of ALB was dose related for all three STH. For hookworm, the time required for sustained clearance was longer (4.3 years, P < 0.001) for participants who took zero doses per year and shorter (3.4 years, P = 0.112) for participants who took two doses per year compared to those who took one dose per year (3.7 years). For Ascaris, the time required to obtain sustained clearance followed the same pattern: 6.1 years (P < 0.001) and 3.2 years (P = 0.004) vs 3.6 years for, zero, two and one dose per year, respectively. For Trichuris, less time was required for sustained clearance (4.2 years, P < 0.001) for fully compliant participants, i.e. those who took two doses per year, than for those who only took one dose per year (5.0 years). ALB was more effective in achieving sustained clearance of STH infection in subjects with light baseline infection intensities compared to those with higher egg counts. CONCLUSION Our results illustrate the importance of MDA compliance at the level of the individual with respect to the STH benefit provided by semiannual ALB MDA, which is used for the elimination of LF in Central Africa.
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Affiliation(s)
- Jérémy T Campillo
- TransVIHMI, Université Montpellier, Institut de Recherche pour le Développement (IRD), INSERM, Montpellier, France
| | - Naomi P Awaca-Uvon
- Ministère de La Santé Publique, Kinshasa, Democratic Republic of the Congo
| | - Jean-Paul Tambwe
- Ministère de La Santé Publique, Kinshasa, Democratic Republic of the Congo
| | | | - Johnny Vlaminck
- Department of Virology, Parasitology and Immunology, Ghent University, Merelbeke, Belgium
| | - Gary J Weil
- Washington University School of Medicine, St. Louis, MO, USA
| | - Michel Boussinesq
- TransVIHMI, Université Montpellier, Institut de Recherche pour le Développement (IRD), INSERM, Montpellier, France
| | - Cédric B Chesnais
- TransVIHMI, Université Montpellier, Institut de Recherche pour le Développement (IRD), INSERM, Montpellier, France
| | - Sébastien D S Pion
- TransVIHMI, Université Montpellier, Institut de Recherche pour le Développement (IRD), INSERM, Montpellier, France.
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Manesh A, Meltzer E, Jin C, Britto C, Deodhar D, Radha S, Schwartz E, Rupali P. Typhoid and paratyphoid fever: a clinical seminar. J Travel Med 2021; 28:6129661. [PMID: 33550411 DOI: 10.1093/jtm/taab012] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/07/2021] [Indexed: 01/06/2023]
Abstract
Rationale for review: Enteric fever (EF) caused by Salmonella enterica subspecies enterica serovar Typhi (Salmonella Typhi) and S. Paratyphi (Salmonella Paratyphi) remains an important cause of infectious morbidity and mortality in many low-income countries and, therefore, still poses a major infectious risk for travellers to endemic countries. Main findings: Although the global burden of EF has decreased over the past two decades, prevalence of EF remains high in Asia and Africa, with the highest prevalence reported from the Indian subcontinent. These statistics are mirrored by data on travel-related EF. Widespread and increasing antimicrobial resistance has narrowed treatment options for travel-related EF. Ceftriaxone- and azithromycin-based therapies are commonly used, even with the emergence of extremely drug-resistant typhoid in Pakistan. Preventive measures among locals and travellers include provision of safe food and water and vaccination. Food and water precautions offer limited protection, and the efficacy of Salmonella Typhi vaccines is only moderate signifying the need for travellers to be extra cautious. Recommendations: Improvement in the diagnosis of typhoid with high degree of clinical suspicion, better diagnostic assays, early and accurate detection of resistance, therapy with appropriate drugs, improvements in hygiene and sanitation with provision of safe drinking water in endemic areas and vaccination among travellers as well as in the endemic population are keys to controlling typhoid. While typhoid vaccines are recommended for travellers to high-risk areas, moderate efficacy and inability to protect against Salmonella Paratyphi are limitations to bear in mind. Improved Salmonella Typhi vaccines and vaccines against Salmonella Paratyphi A are required.
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Affiliation(s)
- Abi Manesh
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Eyal Meltzer
- Department of Medicine `C', Center for Geographic Medicine, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Celina Jin
- Oxford Vaccine Group, Department of Pediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Carl Britto
- Oxford Vaccine Group, Department of Pediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Divya Deodhar
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Sneha Radha
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Eli Schwartz
- Department of Medicine `C', Center for Geographic Medicine, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Priscilla Rupali
- Department of Infectious Diseases, Christian Medical College, Vellore, India
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14
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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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15
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Qamar FN, Yousafzai MT, Dehraj IF, Shakoor S, Irfan S, Hotwani A, Hunzai MJ, Thobani RS, Rahman N, Mehmood J, Hemlock C, Memon AM, Andrews JR, Luby SP, Garrett DO, Longley AT, Date K, Saha SK. Antimicrobial Resistance in Typhoidal Salmonella: Surveillance for Enteric Fever in Asia Project, 2016-2019. Clin Infect Dis 2020; 71:S276-S284. [PMID: 33258934 PMCID: PMC7705872 DOI: 10.1093/cid/ciaa1323] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Clinicians have limited therapeutic options for enteric as a result of increasing antimicrobial resistance, and therefore typhoid vaccination is recommended as a preventive measure. As a part of the Surveillance for Enteric Fever in Asia Project (SEAP), we investigated the extent measured the burden of antimicrobial resistance (AMR) among confirmed enteric fever cases in Bangladesh, Nepal, and Pakistan. METHODS From September 2016-September 2019, SEAP recruited study participants of all age groups from its outpatient, inpatient, hospital laboratory, laboratory network, and surgical sites who had a diagnosis of febrile illness that was either suspected or blood culture confirmed for enteric fever. Antimicrobial resistance of isolates was determined by disc diffusion using Clinical and Laboratory Standard Institute cut-off points. We reported the frequency of multidrug resistance (MDR)(resistance to ampicillin, cotrimoxazole, and chloramphenicol), extensive drug resistance (XDR) (MDR plus non-susceptible to fluoroquinolone and any 3rd generation cephalosporins), and fluoroquinolone (FQ) and azithromycin non-susceptibility. RESULTS We enrolled 8,705 blood culture confirmed enteric fever cases: 4,873 (56%) from Bangladesh, 1,602 (18%) from Nepal and 2,230 (26%) from Pakistan. Of these, 7,591 (87%) were Salmonella Typhi and 1114 (13%) were S. Paratyphi. MDR S. Typhi was identified in 17% (701/4065) of isolates in Bangladesh, and 1% (19/1342) in Nepal. In Pakistan, 16 % (331/2084) of S. Typhi isolates were MDR, and 64% (1319/2074) were XDR. FQ nonsusceptibility among S. Typhi isolates was 98% in Bangladesh, 87% in Nepal, and 95% in Pakistan. Azithromycin non-susceptibility was detected in 77 (2%) in Bangladesh, 9 (.67%) in Nepal and 9 (.59%) isolates in Pakistan. In Pakistan, three (2%) S. Paratyphi isolates were MDR; no MDR S. Paratyphi was reported from Bangladesh or Nepal. CONCLUSIONS Although AMR against S. Paratyphi was low across the three countries, there was widespread drug resistance among S. Typhi, including FQ non-susceptibility and the emergence of XDR S. Typhi in Pakistan, limiting treatment options. As typhoid conjugate vaccine (TCV) is rolled out, surveillance should continue to monitor changes in AMR to inform policies and to monitor drug resistance in S. Paratyphi, for which there is no vaccine.
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Affiliation(s)
- Farah N Qamar
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Mohammad T Yousafzai
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Irum F Dehraj
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Sadia Shakoor
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Seema Irfan
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Aneeta Hotwani
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Muhammad J Hunzai
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Rozina S Thobani
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Najeeb Rahman
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Junaid Mehmood
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan
| | - Caitlin Hemlock
- Applied Epidemiology, Sabin Vaccine Institute, Washington, DC, USA
| | | | - Jason R Andrews
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - Stephen P Luby
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - Denise O Garrett
- Applied Epidemiology, Sabin Vaccine Institute, Washington, DC, USA
| | - Ashley T Longley
- National Foundation for the Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Kashmira Date
- National Foundation for the Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Samir K Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Bangladesh
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Abstract
Efforts to produce vaccines against SARS and MERS were prematurely halted since their scope was perceived to be geographically restricted and they were subsequently categorized as neglected diseases. However, when a similar virus spread globally triggering the COVID-19 pandemic, we were harshly reminded that several other neglected diseases might also be waiting for the perfect opportunity to become mainstream. As climate change drives urbanization, natural selection of pathogens and their intermediate vectors and reservoirs, the risk of neglected diseases emerging within a larger susceptible pool becomes an even greater threat. Availability of a vaccine for COVID-19 is widely considered the only way to end this pandemic. Similarly, vaccines are also seen as the best tools available to control the spread of neglected (sometimes referred to as emerging or re-emerging) diseases, until the water, hygiene and sanitation infrastructure is improved in areas of their prevalence. Vaccine production is usually cost and labour intensive and thus minimal funding is directed towards controlling and eliminating neglected diseases (NDs). A customised but sustainable approach is needed to develop and deploy vaccines against NDs. While safety, efficacy and public trust are the three main success pillars for most vaccines, affordability is vital when formulating vaccines for neglected diseases.
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Jamka LP, Simiyu KW, Bentsi-Enchill AD, Mwisongo AJ, Matzger H, Marfin AA, Pollard AJ, Neuzil KM. Accelerating Typhoid Conjugate Vaccine Introduction: What Can Be Learned From Prior New Vaccine Introduction Initiatives? Clin Infect Dis 2019; 68:S171-S176. [PMID: 30845328 PMCID: PMC6405264 DOI: 10.1093/cid/ciy1118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The health consequences of typhoid, including increasing prevalence of drug-resistant strains, can stress healthcare systems. While vaccination is one of the most successful and cost-effective health interventions, vaccine introduction can take years and require considerable effort. The Typhoid Vaccine Acceleration Consortium (TyVAC) employs an integrated, proactive approach to accelerate the introduction of a new typhoid conjugate vaccine to reduce the burden of typhoid in countries eligible for support from Gavi, the Vaccine Alliance. TyVAC and its partners are executing a plan, informed by prior successful vaccine introductions, and tailored to the nuances of typhoid disease and the typhoid conjugate vaccine. The iterative process detailed herein summarizes the strategy and experience gained from the first 2 years of the project.
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Affiliation(s)
- Leslie P Jamka
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Kenneth W Simiyu
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
| | - Adwoa D Bentsi-Enchill
- Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland
| | - Aziza J Mwisongo
- Center for Vaccine Innovation and Access, PATH, Seattle, Washington
| | - Helen Matzger
- Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland
| | - Anthony A Marfin
- Center for Vaccine Innovation and Access, PATH, Seattle, Washington
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
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Affiliation(s)
- Andrew J Pollard
- Oxford Vaccine Group, University of Oxford, and the National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
| | - Anthony A Marfin
- Center for Vaccine Innovation and Access, PATH, Seattle, Washington
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
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Bhatia R. Vaccines as a Tool to Contain Antimicrobial Resistance. Indian J Med Microbiol 2019; 37:1-4. [DOI: 10.4103/ijmm.ijmm_19_223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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