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Anteneh LM, Lokonon BE, Kakaï RG. Modelling techniques in cholera epidemiology: A systematic and critical review. Math Biosci 2024; 373:109210. [PMID: 38777029 DOI: 10.1016/j.mbs.2024.109210] [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: 10/21/2023] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Diverse modelling techniques in cholera epidemiology have been developed and used to (1) study its transmission dynamics, (2) predict and manage cholera outbreaks, and (3) assess the impact of various control and mitigation measures. In this study, we carry out a critical and systematic review of various approaches used for modelling the dynamics of cholera. Also, we discuss the strengths and weaknesses of each modelling approach. A systematic search of articles was conducted in Google Scholar, PubMed, Science Direct, and Taylor & Francis. Eligible studies were those concerned with the dynamics of cholera excluding studies focused on models for cholera transmission in animals, socio-economic factors, and genetic & molecular related studies. A total of 476 peer-reviewed articles met the inclusion criteria, with about 40% (32%) of the studies carried out in Asia (Africa). About 52%, 21%, and 9%, of the studies, were based on compartmental (e.g., SIRB), statistical (time series and regression), and spatial (spatiotemporal clustering) models, respectively, while the rest of the analysed studies used other modelling approaches such as network, machine learning and artificial intelligence, Bayesian, and agent-based approaches. Cholera modelling studies that incorporate vector/housefly transmission of the pathogen are scarce and a small portion of researchers (3.99%) considers the estimation of key epidemiological parameters. Vaccination only platform was utilized as a control measure in more than half (58%) of the studies. Research productivity in cholera epidemiological modelling studies have increased in recent years, but authors used diverse range of models. Future models should consider incorporating vector/housefly transmission of the pathogen and on the estimation of key epidemiological parameters for the transmission of cholera dynamics.
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Affiliation(s)
- Leul Mekonnen Anteneh
- Laboratoire de Biomathématiques et d'Estimations Forestières, University of Abomey-Calavi, Cotonou, Benin.
| | - Bruno Enagnon Lokonon
- Laboratoire de Biomathématiques et d'Estimations Forestières, University of Abomey-Calavi, Cotonou, Benin
| | - Romain Glèlè Kakaï
- Laboratoire de Biomathématiques et d'Estimations Forestières, University of Abomey-Calavi, Cotonou, Benin
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Malembaka EB, Bugeme PM, Hutchins C, Xu H, Hulse JD, Demby MN, Gallandat K, Saidi JM, Rumedeka BB, Itongwa M, Tshiwedi-Tsilabia E, Kitoga F, Bodisa-Matamu T, Kavunga-Membo H, Bengehya J, Kulondwa JC, Debes AK, Taty N, Lee EC, Lunguya O, Lessler J, Leung DT, Cumming O, Okitayemba PW, Mukadi-Bamuleka D, Knee J, Azman AS. Effectiveness of one dose of killed oral cholera vaccine in an endemic community in the Democratic Republic of the Congo: a matched case-control study. THE LANCET. INFECTIOUS DISEASES 2024; 24:514-522. [PMID: 38246191 PMCID: PMC11043051 DOI: 10.1016/s1473-3099(23)00742-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/07/2023] [Accepted: 11/21/2023] [Indexed: 01/23/2024]
Abstract
BACKGROUND A global shortage of cholera vaccines has increased the use of single-dose regimens, rather than the standard two-dose regimen. There is sparse evidence on single-dose protection, particularly in children. In 2020, a mass vaccination campaign was conducted in Uvira, an endemic urban setting in eastern Democratic Republic of the Congo, resulting in largely single-dose coverage. We examined the effectiveness of a single-dose of the oral cholera vaccine Euvichol-Plus in this high-burden setting. METHODS In this matched case-control study, we recruited individuals with medically attended confirmed cholera in the two cholera treatment facilities in the city of Uvira. The control group consisted of age-matched, sex-matched, and neighbourhood-matched community individuals. We recruited across two distinct periods: Oct 14, 2021, to March 10, 2022 (12-17 months after vaccination), and Nov 21, 2022, to Oct 18, 2023 (24-36 months after vaccination). Study staff administered structured questionnaires to all participants to capture demographics, household conditions, potential confounding variables, and vaccination status. The odds of vaccination for the case and control groups were contrasted in conditional logistic regression models to estimate unadjusted and adjusted vaccine effectiveness. FINDINGS We enrolled 658 individuals with confirmed cholera and 2274 matched individuals for the control group. 99 (15·1%) individuals in the case group were younger than 5 years at the time of vaccination. The adjusted single-dose vaccine effectiveness was 52·7% (95% CI 31·4 to 67·4) 12-17 months after vaccination and 44·7% (24·8 to 59·4) 24-36 months after vaccination. Although protection in the first 12-17 months after vaccination was similar for children aged 1-4 years and older individuals, the estimate of protection in children aged 1-4 years appeared to wane during the third year after vaccination (adjusted vaccine effectiveness 32·9%, 95% CI -30·7 to 65·5), with CIs spanning the null. INTERPRETATION A single dose of Euvichol-Plus provided substantial protection against medically attended cholera for at least 36 months after vaccination in this cholera-endemic setting. Although the evidence provides support for similar levels of protection in young children and others in the short term, protection among children younger than 5 years might wane significantly during the third year after vaccination. FUNDING Wellcome Trust and Gavi, the Vaccine Alliance.
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Affiliation(s)
- Espoir Bwenge Malembaka
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA; Centre for Tropical Diseases and Global Health (CTDGH), Université Catholique de Bukavu, Bukavu, Democratic Republic of the Congo
| | - Patrick Musole Bugeme
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA; Centre for Tropical Diseases and Global Health (CTDGH), Université Catholique de Bukavu, Bukavu, Democratic Republic of the Congo
| | - Chloe Hutchins
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Hanmeng Xu
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - Juan Dent Hulse
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - Maya N Demby
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - Karin Gallandat
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Jaime Mufitini Saidi
- Ministère de la Santé Publique, Hygiène et Prévention, Zone de Santé d'Uvira, Uvira, Democratic Republic of the Congo
| | | | | | | | - Faida Kitoga
- Rodolphe Merieux INRB-Goma Laboratory, Goma, North Kivu, Democratic Republic of the Congo
| | - Tavia Bodisa-Matamu
- Rodolphe Merieux INRB-Goma Laboratory, Goma, North Kivu, Democratic Republic of the Congo
| | - Hugo Kavunga-Membo
- Rodolphe Merieux INRB-Goma Laboratory, Goma, North Kivu, Democratic Republic of the Congo; Institut National de Recherche Biomédicale, INRB, Kinshasa, Democratic Republic of the Congo
| | - Justin Bengehya
- Ministère de la Santé Publique, Hygiène et Prévention, Division Provinciale de la Sante' Publique du Sud-Kivu, Bukavu, Democratic Republic of the Congo
| | - Jean-Claude Kulondwa
- Ministère de la Santé Publique, Hygiène et Prévention, Division Provinciale de la Sante' Publique du Sud-Kivu, Bukavu, Democratic Republic of the Congo
| | - Amanda K Debes
- Department of International Health, Johns Hopkins University, Baltimore, MD, USA
| | - Nagède Taty
- PNECHOL-MD, Community IMCI, Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Elizabeth C Lee
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - Octavie Lunguya
- Institut National de Recherche Biomédicale, INRB, Kinshasa, Democratic Republic of the Congo; Service of Microbiology, Department of Medical Biology, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA; University of North Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Daniel T Leung
- Division of Infectious Diseases and Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Oliver Cumming
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Daniel Mukadi-Bamuleka
- Rodolphe Merieux INRB-Goma Laboratory, Goma, North Kivu, Democratic Republic of the Congo; Institut National de Recherche Biomédicale, INRB, Kinshasa, Democratic Republic of the Congo; Service of Microbiology, Department of Medical Biology, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jackie Knee
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Andrew S Azman
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA; Geneva Centre for Emerging Viral Diseases and Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland.
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Matias WR, Guillaume Y, Cene Augustin G, Vissieres K, Ternier R, Slater DM, Harris JB, Franke MF, Ivers LC. Effectiveness of the Euvichol® oral cholera vaccine at 2 years: A case-control and bias-indicator study in Haiti. Int J Infect Dis 2024; 139:153-158. [PMID: 38000510 PMCID: PMC10784151 DOI: 10.1016/j.ijid.2023.11.022] [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: 08/01/2023] [Revised: 10/21/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023] Open
Abstract
OBJECTIVES The World Health Organization recommends the use of oral cholera vaccine (OCV) in cholera control efforts. Euvichol®, pre-qualified in 2015, is the leading component of the Global OCV stockpile, but data on its field effectiveness are limited. To evaluate Euvichol® vaccine effectiveness (VE), we conducted a case-control study between September 2018 to March 2020 following an OCV campaign in November 2017 in Haiti. METHODS Cases were individuals with acute watery diarrhea. Stool samples were tested by culture and real-time polymerase chain reaction of the Vibrio cholerae ctxA gene. Cases were matched to four community controls without diarrhea by residence, enrollment time, age, and gender, and interviewed for sociodemographics, risk factors, and self-reported vaccination. Cholera cases were analyzed by conditional logistic regression in the VE study. Non-cholera diarrhea cases were analyzed in a bias-indicator study. RESULTS We enrolled 15 cholera cases matched to 60 controls, and 63 non-cholera diarrhea cases matched to 249 controls. In the VE analysis, eight (53%) cases reported vaccination with any number of doses compared to 43 (72%) controls. Adjusted two-dose OCV VE was 69% (95% CI -71 to 94%). CONCLUSIONS Between 10-27 months after vaccination, Euvichol® was effective and similar to Shanchol™, suggesting that it can serve as one component of multi-sectoral comprehensive cholera control.
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Affiliation(s)
- Wilfredo R Matias
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA; Division of Infectious Diseases, Brigham and Women's Hospital, Boston, USA; Center for Global Health, Massachusetts General Hospital, Boston, USA.
| | | | | | | | | | - Damien M Slater
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA; Department of Pediatrics, Harvard Medical School, Boston, USA
| | - Jason B Harris
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA; Department of Pediatrics, Harvard Medical School, Boston, USA
| | - Molly F Franke
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, USA
| | - Louise C Ivers
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA; Center for Global Health, Massachusetts General Hospital, Boston, USA; Department of Global Health and Social Medicine, Harvard Medical School, Boston, USA; Harvard Global Health Institute, Cambridge, USA
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Huo Y, Yang Y, Halloran ME, Longini IM, Dean NE. Hypothesis testing and sample size considerations for the test-negative design. RESEARCH SQUARE 2023:rs.3.rs-3783493. [PMID: 38234799 PMCID: PMC10793497 DOI: 10.21203/rs.3.rs-3783493/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
The test-negative design (TND) is an observational study design to evaluate vaccine effectiveness (VE) that enrolls individuals receiving diagnostic testing for a target disease as part of routine care. VE is estimated as one minus the adjusted odds ratio of testing positive versus negative comparing vaccinated and unvaccinated patients. Although the TND is related to case-control studies, it is distinct in that the ratio of test-positive cases to test-negative controls is not typically pre-specified. For both types of studies, sparse cells are common when vaccines are highly effective. We consider the implications of these features on power for the TND. We use simulation studies to explore three hypothesis-testing procedures and associated sample size calculations for case-control and TND studies. These tests, all based on a simple logistic regression model, are a standard Wald test, a continuity-corrected Wald test, and a score test. The Wald test performs poorly in both case-control and TND when VE is high because the number of vaccinated test-positive cases can be low or zero. Continuity corrections help to stabilize the variance but induce bias. We observe superior performance with the score test as the variance is pooled under the null hypothesis of no group differences. We recommend using a score-based approach to design and analyze both case-control and TND. We propose a modification to the TND score sample size to account for additional variability in the ratio of controls over cases. This work expands our understanding of the data mechanisms of the TND.
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Affiliation(s)
- Yanan Huo
- Gilead Sciences, Foster City, CA, USA
| | - Yang Yang
- Department of Statistics, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
| | | | - Ira M Longini
- Department of Biostatistics, University of Florida, Gainesville, FL, USA
| | - Natalie E Dean
- Department of Biostatistics & Bioinformatics, Emory University, Atlanta, GA, USA
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Abdelmagid N, Southgate RJ, Alhaffar M, Ahmed M, Bani H, Mounier-Jack S, Dahab M, Checchi F, Sabahelzain MM, Nor B, Rao B, Singh NS. The Governance of Childhood Vaccination Services in Crisis Settings: A Scoping Review. Vaccines (Basel) 2023; 11:1853. [PMID: 38140257 PMCID: PMC10747651 DOI: 10.3390/vaccines11121853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
The persistence of inadequate vaccination in crisis-affected settings raises concerns about decision making regarding vaccine selection, timing, location, and recipients. This review aims to describe the key features of childhood vaccination intervention design and planning in crisis-affected settings and investigate how the governance of childhood vaccination is defined, understood, and practised. We performed a scoping review of 193 peer-reviewed articles and grey literature on vaccination governance and service design and planning. We focused on 41 crises between 2010 and 2021. Following screening and data extraction, our analysis involved descriptive statistics and applying the governance analysis framework to code text excerpts, employing deductive and inductive approaches. Most documents related to active outbreaks in conflict-affected settings and to the mass delivery of polio, cholera, and measles vaccines. Information on vaccination modalities, target populations, vaccine sources, and funding was limited. We found various interpretations of governance, often implying hierarchical authority and regulation. Analysis of governance arrangements suggests a multi-actor yet fragmented governance structure, with inequitable actor participation, ineffective actor collaboration, and a lack of a shared strategic vision due to competing priorities and accountabilities. Better documentation of vaccination efforts during emergencies, including vaccination decision making, governance, and planning, is needed. We recommend empirical research within decision-making spaces.
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Affiliation(s)
- Nada Abdelmagid
- Department of Infectious Disease Epidemiology and International Health, Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Health in Humanitarian Crises Centre, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | | | - Mervat Alhaffar
- Department of Infectious Disease Epidemiology and International Health, Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Syria Research Group (SYRG), Co-Hosted by the London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK and Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore
| | - Matab Ahmed
- School of Health Sciences, Ahfad University for Women (AUW), Omdurman P.O. Box 167, Sudan
| | - Hind Bani
- School of Health Sciences, Ahfad University for Women (AUW), Omdurman P.O. Box 167, Sudan
| | - Sandra Mounier-Jack
- Department of Global Health and Development, Faculty of Public Health and Policy, The London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK
| | - Maysoon Dahab
- Department of Infectious Disease Epidemiology and International Health, Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Health in Humanitarian Crises Centre, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Francesco Checchi
- Department of Infectious Disease Epidemiology and International Health, Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Health in Humanitarian Crises Centre, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Majdi M. Sabahelzain
- School of Health Sciences, Ahfad University for Women (AUW), Omdurman P.O. Box 167, Sudan
- School of Public Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2050, Australia
| | - Barni Nor
- Department of Women’s and Children’s Health, Uppsala University, 751 23 Uppsala, Sweden
| | - Bhargavi Rao
- Department of Global Health and Development, Faculty of Public Health and Policy, The London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK
| | - Neha S. Singh
- Health in Humanitarian Crises Centre, The London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Department of Global Health and Development, Faculty of Public Health and Policy, The London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK
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Wiens KE, Xu H, Zou K, Mwaba J, Lessler J, Malembaka EB, Demby MN, Bwire G, Qadri F, Lee EC, Azman AS. Estimating the proportion of clinically suspected cholera cases that are true Vibrio cholerae infections: A systematic review and meta-analysis. PLoS Med 2023; 20:e1004286. [PMID: 37708235 PMCID: PMC10538743 DOI: 10.1371/journal.pmed.1004286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 09/28/2023] [Accepted: 08/25/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND Cholera surveillance relies on clinical diagnosis of acute watery diarrhea. Suspected cholera case definitions have high sensitivity but low specificity, challenging our ability to characterize cholera burden and epidemiology. Our objective was to estimate the proportion of clinically suspected cholera that are true Vibrio cholerae infections and identify factors that explain variation in positivity. METHODS AND FINDINGS We conducted a systematic review of studies that tested ≥10 suspected cholera cases for V. cholerae O1/O139 using culture, PCR, and/or a rapid diagnostic test. We searched PubMed, Embase, Scopus, and Google Scholar for studies that sampled at least one suspected case between January 1, 2000 and April 19, 2023, to reflect contemporary patterns in V. cholerae positivity. We estimated diagnostic test sensitivity and specificity using a latent class meta-analysis. We estimated V. cholerae positivity using a random-effects meta-analysis, adjusting for test performance. We included 119 studies from 30 countries. V. cholerae positivity was lower in studies with representative sampling and in studies that set minimum ages in suspected case definitions. After adjusting for test performance, on average, 52% (95% credible interval (CrI): 24%, 80%) of suspected cases represented true V. cholerae infections. After adjusting for test performance and study methodology, the odds of a suspected case having a true infection were 5.71 (odds ratio 95% CrI: 1.53, 15.43) times higher when surveillance was initiated in response to an outbreak than in non-outbreak settings. Variation across studies was high, and a limitation of our approach was that we were unable to explain all the heterogeneity with study-level attributes, including diagnostic test used, setting, and case definitions. CONCLUSIONS In this study, we found that burden estimates based on suspected cases alone may overestimate the incidence of medically attended cholera by 2-fold. However, accounting for cases missed by traditional clinical surveillance is key to unbiased cholera burden estimates. Given the substantial variability in positivity between settings, extrapolations from suspected to confirmed cases, which is necessary to estimate cholera incidence rates without exhaustive testing, should be based on local data.
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Affiliation(s)
- Kirsten E. Wiens
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Epidemiology and Biostatistics, College of Public Health, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Hanmeng Xu
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Kaiyue Zou
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - John Mwaba
- Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
- Department of Pathology and Microbiology, University Teaching Hospital, Lusaka, Zambia
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Espoir Bwenge Malembaka
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Center for Tropical Diseases and Global Health (CTDGH), Université Catholique de Bukavu, Bukavu, Democratic Republic of the Congo
| | - Maya N. Demby
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Godfrey Bwire
- Division of Public Health Emergency Preparedness and Response, Ministry of Health, Kampala, Uganda
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Elizabeth C. Lee
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Andrew S. Azman
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Geneva Centre for Emerging Viral Diseases, Geneva University Hospitals, Geneva, Switzerland
- Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland
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Buliva E, Elnossery S, Okwarah P, Tayyab M, Brennan R, Abubakar A. Cholera prevention, control strategies, challenges and World Health Organization initiatives in the Eastern Mediterranean Region: A narrative review. Heliyon 2023; 9:e15598. [PMID: 37153427 PMCID: PMC10160509 DOI: 10.1016/j.heliyon.2023.e15598] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/01/2023] [Accepted: 04/17/2023] [Indexed: 05/09/2023] Open
Abstract
The resurgence of cholera is presenting unusual challenges in the Eastern Mediterranean Region (EMR), where it is considered endemic in nine-member states. The risk of a cholera outbreak spreading to non-endemic countries remains high. We discuss the regional trends of cholera, regional burden, and challenges with a focus on World Health Organization (WHO) initiatives in the region that could be useful in preventing and controlling the disease in similar contexts. Despite significant progress in the control of cholera worldwide, the disease continues to be a major public health problem across the region, where it constitutes both an emerging and re-emerging threat. Recurring cholera outbreaks are an indication of deprived water and sanitation conditions as well as weak health systems, contributing to the transmission and spread of the cholera infection. We note that despite the challenges in eliminating cholera in the region, effective implementation of the proposed WHO EMR Strategic framework, among other measures, could sustain the region's cholera prevention, preparedness, and response needs.
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Affiliation(s)
- Evans Buliva
- World Health Organization (WHO) Regional Office for the Eastern Mediterranean, Cairo, Egypt
| | - Sherein Elnossery
- World Health Organization (WHO) Regional Office for the Eastern Mediterranean, Cairo, Egypt
| | - Patrick Okwarah
- Amref International University (AMIU), School of Public Health, Nairobi, Kenya
| | - Muhammad Tayyab
- World Health Organization (WHO) Regional Office for the Eastern Mediterranean, Cairo, Egypt
| | - Richard Brennan
- World Health Organization (WHO) Regional Office for the Eastern Mediterranean, Cairo, Egypt
| | - Abdinasir Abubakar
- World Health Organization (WHO) Regional Office for the Eastern Mediterranean, Cairo, Egypt
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Gelormini M, Gripenberg M, Marke D, Murray M, Yambasu S, Koblo Kamara M, Michael Thomas C, Donald Sonne K, Sang S, Kayita J, Pezzoli L, Caleo G. Coverage survey and lessons learned from a pre-emptive cholera vaccination campaign in urban and rural communities affected by landslides and floods in Freetown Sierra Leone. Vaccine 2023; 41:2397-2403. [PMID: 36872143 PMCID: PMC10102719 DOI: 10.1016/j.vaccine.2023.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/02/2022] [Accepted: 01/11/2023] [Indexed: 03/06/2023]
Abstract
BACKGROUND On 14 August 2017, massive landslides and floods hit Freetown (Sierra Leone). More than 1,000 people lost their lives while approximately 6,000 people were displaced. The areas most affected included parts of the town with challenged access to basic water and sanitation facilities, with communal water sources likely contaminated by the disaster. To avert a possible cholera outbreak following this emergency, the Ministry of Health and Sanitation (MoHS), supported by the World Health Organization (WHO) and international partners, including Médecins Sans Frontières (MSF) and UNICEF, launched a two-dose pre-emptive vaccination campaign using Euvichol™, an oral cholera vaccine (OCV). METHODS We conducted a stratified cluster survey to estimate vaccination coverage during the OCV campaign and also monitor adverse events. The study population - subsequently stratified by age group and residence area type (urban/rural) - included all individuals aged 1 year or older, living in one of the 25 communities targeted for vaccination. RESULTS In total 3,115 households were visited, 7,189 individuals interviewed; 2,822 (39%) people in rural and 4,367 (61%) in urban areas. The two-dose vaccination coverage was 56% (95% confidence interval (CI): 51.0-61.5), 44% (95%CI: 35.2-53.0) in rural and 57% (95%CI: 51.6-62.8) in urban areas. Vaccination coverage with at least one dose was 82% (95%CI: 77.3-85.5), 61% (95%CI: 52.0-70.2) in rural and 83% (95%CI: 78.5-87.1) in urban areas. CONCLUSIONS The Freetown OCV campaign exemplified a timely public health intervention to prevent a cholera outbreak, even if coverage was lower than expected. We hypothesised that vaccination coverage in Freetown was sufficient in providing at least short-term immunity to the population. However, long-term interventions to ensure access to safe water and sanitation are needed.
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Affiliation(s)
| | | | - Dennis Marke
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Mariama Murray
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | | | | | | | - Sibylle Sang
- Médecins Sans Frontières, OCA, Amsterdam, the Netherlands
| | - Janet Kayita
- World Health Organization, Freetown, Sierra Leone
| | | | - Grazia Caleo
- Médecins Sans Frontières, OCA, Amsterdam, the Netherlands
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Sialubanje C, Kapina M, Chewe O, Matapo BB, Ngomah AM, Gianetti B, Ngosa W, Kasonde M, Musonda K, Mulenga M, Michelo C, Sinyange N, Bobo P, Zyambo K, Mazyanga L, Bakyaita N, Mukonka VM. Effectiveness of two doses of Euvichol-plus oral cholera vaccine in response to the 2017/2018 outbreak: a matched case-control study in Lusaka, Zambia. BMJ Open 2022; 12:e066945. [PMID: 36368745 PMCID: PMC9660660 DOI: 10.1136/bmjopen-2022-066945] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Zambia experienced a major cholera outbreak in 2017-2018, with more than 5905 cases reported countrywide, predominantly from the peri-urban slums of Lusaka city. The WHO recommends the use of oral cholera vaccines (OCVs) together with traditional control measures, including health promotion, provision of safe water and improving sanitation, in cholera endemic areas and during cholera outbreaks. In response to this outbreak, the Zambian government implemented the OVC campaign and administered the Euvichol-plus vaccine in the high-risk subdistricts of Lusaka. Although OCVs have been shown to be effective in preventing cholera infection in cholera endemic and outbreak settings, the effectiveness of the Euvichol-plus vaccine has not yet been evaluated in Zambia. This study aimed to determine the effectiveness of two doses of OCV administered during the 2017/2018 vaccination campaign. METHODS We conducted a matched case-control study involving 79 cases and 316 controls following the mass vaccination campaign in the four subdistricts of Lusaka (Chawama, Chipata, Kanyama and Matero). Matching of controls was based on the place of residence, age and sex. Conditional logistic regression was used for analysis. Adjusted OR (AOR), 95% CI and vaccine effectiveness (1-AOR) for two doses of Euvichol-plus vaccine and any dose were estimated (p<0.05). RESULTS The AOR vaccine effectiveness for two doses of Euvichol-plus OCV was 81.0% (95% CI 66.0% to 78.0%; p<0.01). Secondary analysis showed that vaccine effectiveness for any dose was 74.0% (95% CI 50.0% to 86.0%; p<0.01). CONCLUSION These findings show that two doses of Euvichol-plus OCV are effective in a cholera outbreak setting in Lusaka, Zambia. The findings also indicate that two doses are more effective than a single dose and thus support the use of two doses of the vaccine as part of an integrated intervention to cholera control during outbreaks.
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Affiliation(s)
- Cephas Sialubanje
- School of Public Health, Levy Mwanawasa Medical University, Lusaka, Zambia
| | - Muzala Kapina
- Zambia National Public Health Institute, Lusaka, Zambia
| | - Orbrie Chewe
- Surveillance and Disease Intelligence, Zambia National Public Health Institute, Lusaka, Zambia
- Ministry of health Zambia, Lusaka, Zambia
| | - Belem Blamwell Matapo
- World Health Organization, Lusaka, Zambia
- Disease Surveillance, World Health Organisation, Lusaka, Zambia
| | - Albertina Moraes Ngomah
- Communication Information & Research, Zambia National Public Health Institute, Lusaka, Zambia
| | | | - William Ngosa
- Communication Information & Research, Zambia National Public Health Institute, Lusaka, Zambia
| | - Mpanga Kasonde
- Laboratory System and Networks, Zambia National Public Health Institute, Lusaka, Zambia
| | - Kunda Musonda
- Ministry of health Zambia, Lusaka, Zambia
- Laboratory Systems and Networks, Zambia National Public Health Institute, Lusaka, Zambia
| | | | - C Michelo
- University of Zambia School of Public Health, Lusaka, Zambia
| | - Nyambe Sinyange
- Epidemic Preparedness & Response, Zambia National Public Health Institute, Lusaka, Zambia
| | | | | | - Lucy Mazyanga
- Zambia National Public Health Institute, Lusaka, Zambia
| | | | - Victor M Mukonka
- Zambia National Public Health Institute, Lusaka, Zambia
- The Copperbelt University School of Medicine, Kitwe, Zambia
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Ratnayake R, Peyraud N, Ciglenecki I, Gignoux E, Lightowler M, Azman AS, Gakima P, Ouamba JP, Sagara JA, Ndombe R, Mimbu N, Ascorra A, Welo PO, Mukamba Musenga E, Miwanda B, Boum Y, Checchi F, Edmunds WJ, Luquero F, Porten K, Finger F. Effectiveness of case-area targeted interventions including vaccination on the control of epidemic cholera: protocol for a prospective observational study. BMJ Open 2022; 12:e061206. [PMID: 35793924 PMCID: PMC9260795 DOI: 10.1136/bmjopen-2022-061206] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION Cholera outbreaks in fragile settings are prone to rapid expansion. Case-area targeted interventions (CATIs) have been proposed as a rapid and efficient response strategy to halt or substantially reduce the size of small outbreaks. CATI aims to deliver synergistic interventions (eg, water, sanitation, and hygiene interventions, vaccination, and antibiotic chemoprophylaxis) to households in a 100-250 m 'ring' around primary outbreak cases. METHODS AND ANALYSIS We report on a protocol for a prospective observational study of the effectiveness of CATI. Médecins Sans Frontières (MSF) plans to implement CATI in the Democratic Republic of the Congo (DRC), Cameroon, Niger and Zimbabwe. This study will run in parallel to each implementation. The primary outcome is the cumulative incidence of cholera in each CATI ring. CATI will be triggered immediately on notification of a case in a new area. As with most real-world interventions, there will be delays to response as the strategy is rolled out. We will compare the cumulative incidence among rings as a function of response delay, as a proxy for performance. Cross-sectional household surveys will measure population-based coverage. Cohort studies will measure effects on reducing incidence among household contacts and changes in antimicrobial resistance. ETHICS AND DISSEMINATION The ethics review boards of MSF and the London School of Hygiene and Tropical Medicine have approved a generic protocol. The DRC and Niger-specific versions have been approved by the respective national ethics review boards. Approvals are in process for Cameroon and Zimbabwe. The study findings will be disseminated to the networks of national cholera control actors and the Global Task Force for Cholera Control using meetings and policy briefs, to the scientific community using journal articles, and to communities via community meetings.
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Affiliation(s)
- Ruwan Ratnayake
- Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Epicentre, Paris, France
| | | | | | | | | | - Andrew S Azman
- Médecins Sans Frontières, Geneva, Switzerland
- Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | | | | | | | | | | | - Placide Okitayemba Welo
- Programme National d'Elimination du Choléra et de lutte contre les autres Maladies Diarrhéiques, Kinshasa, Congo (the Democratic Republic of the)
| | | | - Berthe Miwanda
- Institut National de Recherche Biologique, Kinshasa, Congo (the Democratic Republic of the)
| | | | - Francesco Checchi
- Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - W John Edmunds
- Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Francisco Luquero
- Epicentre, Paris, France
- GAVI the Vaccine Alliance, Geneva, Switzerland
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11
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Leung T, Eaton J, Matrajt L. Optimizing one-dose and two-dose cholera vaccine allocation in outbreak settings: A modeling study. PLoS Negl Trop Dis 2022; 16:e0010358. [PMID: 35442958 PMCID: PMC9060364 DOI: 10.1371/journal.pntd.0010358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/02/2022] [Accepted: 03/25/2022] [Indexed: 11/18/2022] Open
Abstract
Background
A global stockpile of oral cholera vaccine (OCV) was established in 2013 for use in outbreak response and are licensed as two-dose regimens. Vaccine availability, however, remains limited. Previous studies have found that a single dose of OCV may provide substantial protection against cholera.
Methods
Using a mathematical model with two age groups paired with optimization algorithms, we determine the optimal vaccination strategy with one and two doses of vaccine to minimize cumulative overall infections, symptomatic infections, and deaths. We explore counterfactual vaccination scenarios in three distinct settings: Maela, the largest refugee camp in Thailand, with high in- and out-migration; N’Djamena, Chad, a densely populated region; and Haiti, where departments are connected by rivers and roads.
Results
Over the short term under limited vaccine supply, the optimal strategies for all objectives prioritize one dose to the older age group (over five years old), irrespective of setting and level of vaccination coverage. As more vaccine becomes available, it is optimal to administer a second dose for long-term protection. With enough vaccine to cover the whole population with one dose, the optimal strategies can avert up to 30% to 90% of deaths and 36% to 92% of symptomatic infections across the three settings over one year. The one-dose optimal strategies can avert 1.2 to 1.8 times as many cases and deaths compared to the standard two-dose strategy.
Conclusions
In an outbreak setting, speedy vaccination campaigns with a single dose of OCV is likely to avert more cases and deaths than a two-dose pro-rata campaign under a limited vaccine supply.
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Affiliation(s)
- Tiffany Leung
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Julia Eaton
- School of Interdisciplinary Arts and Sciences, University of Washington, Tacoma, Washington, United States of America
| | - Laura Matrajt
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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12
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Ratnayake R, Checchi F, Jarvis CI, Edmunds WJ, Finger F. Inference is bliss: Simulation for power estimation for an observational study of a cholera outbreak intervention. PLoS Negl Trop Dis 2022; 16:e0010163. [PMID: 35171911 PMCID: PMC8887757 DOI: 10.1371/journal.pntd.0010163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 03/01/2022] [Accepted: 01/11/2022] [Indexed: 01/07/2023] Open
Abstract
Background The evaluation of ring vaccination and other outbreak-containment interventions during severe and rapidly-evolving epidemics presents a challenge for the choice of a feasible study design, and subsequently, for the estimation of statistical power. To support a future evaluation of a case-area targeted intervention against cholera, we have proposed a prospective observational study design to estimate the association between the strength of implementation of this intervention across several small outbreaks (occurring within geographically delineated clusters around primary and secondary cases named ‘rings’) and its effectiveness (defined as a reduction in cholera incidence). We describe here a strategy combining mathematical modelling and simulation to estimate power for a prospective observational study. Methodology and principal findings The strategy combines stochastic modelling of transmission and the direct and indirect effects of the intervention in a set of rings, with a simulation of the study analysis on the model results. We found that targeting 80 to 100 rings was required to achieve power ≥80%, using a basic reproduction number of 2.0 and a dispersion coefficient of 1.0–1.5. Conclusions This power estimation strategy is feasible to implement for observational study designs which aim to evaluate outbreak containment for other pathogens in geographically or socially defined rings. From Ebola virus disease outbreaks to the COVID-19 pandemic, the use of real-time evaluations of interventions to contain outbreaks is vital for rapidly estimating impact during the outbreak itself. Such evaluations must be both epidemiologically rigorous and logistically feasible to justify their conduct during an outbreak. In this short report, we report on the process (with R code) and the results of a simulation strategy that we devised for power estimation for a prospective observational study of a novel intervention (“case-area targeted intervention”) to contain cholera case clusters that present at the start of a new outbreak. We used simulation in two ways: mathematical modelling to simulate the impacts of a cholera outbreak and the intervention, and simulation of the study analysis on the model results. The strategy provided estimates of the sample sizes of study units required to achieve 80% and 90% power. Our findings reinforce that this process is feasible to implement for similar observational study designs which aim to evaluate outbreak containment for other pathogens in geographically or socially defined rings.
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Affiliation(s)
- Ruwan Ratnayake
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Epicentre, Paris, France
- * E-mail:
| | - Francesco Checchi
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher I. Jarvis
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - W. John Edmunds
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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13
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McCarty J, Bedell L, De Lame PA, Cassie D, Lock M, Bennett S, Haney D. Update on CVD 103-HgR single-dose, live oral cholera vaccine. Expert Rev Vaccines 2021; 21:9-23. [PMID: 34775892 DOI: 10.1080/14760584.2022.2003709] [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: 01/09/2023]
Abstract
Cholera remains endemic in >50 countries, putting millions at risk, especially young children for whom killed vaccines offer limited protection. An oral, live attenuated vaccine - CVD 103-HgR (Vaxchora vaccine) - was licensed by the US FDA in 2016 for adults aged 18-64 years traveling to endemic regions, based on clinical trials in human volunteers showing the vaccine was well tolerated and conferred 90% efficacy within 10 days. The evidence base for Vaxchora vaccine has expanded with additional clinical trial data, in older adults (aged 46-64 years) and children (aged 2-17 years), demonstrating that the vaccine produces a strong vibriocidal antibody response. Over 68,000 doses have been administered in the United States, with no new safety signals. The dose volume has been reduced in children to improve acceptability, and cold chain requirements are less st ringent, at +2°C─+8°C. The vaccine has recently been licensed in the Untied States for children aged 2-17 years, in Europe for individuals aged ≥2 years, and for home administration in Europe. Next steps include a Phase 4 study in infants (6-23 months). Additional information is needed regarding duration of immunity, the need for and timing of revaccination, and efficacy data from lower-middle-income countries.
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Affiliation(s)
- James McCarty
- Stanford University School of Medicine, 291 Campus Drive, Stanford, California, USA
| | - Lisa Bedell
- Emergent Travel Health, Redwood City, California, USA
| | | | - David Cassie
- Emergent Travel Health, Redwood City, California, USA
| | - Michael Lock
- Emergent Travel Health, Redwood City, California, USA
| | - Sean Bennett
- Adjuvance Technologies, Inc., Lincoln, Nebraska, USA
| | - Douglas Haney
- Emergent Travel Health, Redwood City, California, USA
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14
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Oral Cholera Vaccine Efficacy and Effectiveness. Vaccines (Basel) 2021; 9:vaccines9121482. [PMID: 34960228 PMCID: PMC8708586 DOI: 10.3390/vaccines9121482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/28/2021] [Accepted: 12/08/2021] [Indexed: 11/17/2022] Open
Abstract
Although measuring vaccine efficacy through the conventional phase III study design, randomized, double-blinded controlled trial serves as the "gold standard", effectiveness studies, conducted in the context of a public health program, seek to broaden the understanding of the impact of a vaccine in a real world setting including both individual and population level impacts. Cholera is an acute diarrheal infection caused by the ingestion of food or water contaminated with the bacterium Vibrio cholerae. Since the 1980s, either killed or live oral cholera vaccines (OCVs) have been developed and efficacy and effectiveness studies have been conducted on OCV. Although the results of OCV effectiveness studies sometimes showed outliers, the tendency seen is for effectiveness of the vaccine used in public health settings to be somewhat higher than estimated in randomized controlled trials due to the influence of indirect herd protection. Efficacy and Effectiveness studies both generate important information about the vaccine performance characteristics and its impact when used in real world populations at risk for the disease.
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15
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Roskosky M, Ali M, Upreti SR, Sack D. Spatial clustering of cholera cases in the Kathmandu Valley: implications for a ring vaccination strategy. Int Health 2021; 13:170-177. [PMID: 32761173 PMCID: PMC7902685 DOI: 10.1093/inthealth/ihaa042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 05/26/2020] [Accepted: 07/08/2020] [Indexed: 12/17/2022] Open
Abstract
Background In mid-2016, a cholera outbreak occurred in Kathmandu Valley, Nepal. This retrospective study aims to determine if a reactive, ring vaccination strategy would have been useful in preventing cholera transmission during that outbreak. Methods Data on cholera cases were collected as part of hospital-based surveillance in the Kathmandu Valley in 2016. Global Positioning System (GPS) coordinates were obtained during household visits. Geographic clusters of cases were visually determined and tested statistically for clustering. Cluster size was determined based on the distribution of cases around the index case. Results GPS coordinates for 69 cases were analysed. Six geographic clusters were identified, all of which showed significant clustering of cases. Approximately 85% of cases within a cluster occurred more than 7 d after the index case. The median ring size was 1 km, with a population of 14 000 people. Conclusions Cholera cases were clustered in space and the majority of cases occurred over 1 week after the initial cases in the cluster, allowing for an opportunity to prevent transmission through the use of the vaccine soon after the initial case was identified. A ring vaccination strategy may be especially useful for large urban areas with recurrent seasonal outbreaks but where the specific locations for such outbreaks are not predictable.
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Affiliation(s)
- Mellisa Roskosky
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, 615 N Wolfe Street, MD-21205, USA
| | - Mohammad Ali
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, 615 N Wolfe Street, MD-21205, USA
| | | | - David Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, 615 N Wolfe Street, MD-21205, USA
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16
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Ilboudo PG, Mengel MA, Gessner BD, Ngwira B, Cavailler P, Le Gargasson JB. Cost-effectiveness of a reactive oral cholera immunization campaign using Shanchol™ in Malawi. COST EFFECTIVENESS AND RESOURCE ALLOCATION 2021; 19:17. [PMID: 33691725 PMCID: PMC7945304 DOI: 10.1186/s12962-021-00270-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 03/02/2021] [Indexed: 11/10/2022] Open
Abstract
Background Oral cholera vaccines (OCV) have been recommended as additional measures for the prevention of cholera. However, little is known about the cost-effectiveness of OCV use in sub-Saharan Africa, particularly in reactive outbreak contexts. This study aimed to investigate the cost-effectiveness of the use of OCV Shanchol in response to a cholera outbreak in the Lake Chilwa area, Malawi. Methods The Excel-based Vaccine Introduction Cost-Effectiveness model was used to assess the cost-effectiveness ratios with and without indirect protection. Model input parameters were obtained from cost evaluations and epidemiological studies conducted in Malawi and published literature. One-way sensitivity and threshold analyses of cost-effectiveness ratios were performed. Results Compared with the reference scenario i.e. treatment of cholera cases, the immunization campaign would have prevented 636 and 1 020 cases of cholera without and with indirect protection, respectively. The cost-effectiveness ratios were US$19 212 per death, US$500 per case, and US$738 per DALY averted without indirect protection. They were US$10 165 per death, US$264 per case, and US$391 per DALY averted with indirect protection. The net cost per DALY averted was sensitive to four input parameters, including case fatality rate, duration of immunity (vaccine’s protective duration), discount rate and cholera incidence. Conclusion Relative to the Malawi gross domestic product per capita, the reactive OCV campaign represented a cost-effective intervention, particularly when considering indirect vaccine effects. Results will need to be assessed in other settings, e.g., during campaigns implemented directly by the Ministry of Health rather than by international partners. Supplementary Information The online version contains supplementary material available at 10.1186/s12962-021-00270-y.
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Affiliation(s)
- Patrick G Ilboudo
- Agence de Médecine Préventive, 10 BP 638, Ouagadougou, Burkina Faso.
| | - Martin A Mengel
- Agence de Médecine Préventive, 21 boulevard Pasteur, Paris, 75015, France
| | - Bradford D Gessner
- Agence de Médecine Préventive, 21 boulevard Pasteur, Paris, 75015, France.,Pfizer Inc, Collegeville, PA, USA
| | | | - Philippe Cavailler
- Agence de Médecine Préventive, 21 boulevard Pasteur, Paris, 75015, France
| | - Jean-Bernard Le Gargasson
- Agence de Médecine Préventive, Bureau Ferney-Voltaire, Bat. JB Say, 4e, aile A, 13, chemin du Levant, Ferney-Voltaire, 01210, France
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17
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Deen J, Clemens JD. Licensed and Recommended Inactivated Oral CholeraVaccines: From Development to Innovative Deployment. Trop Med Infect Dis 2021; 6:32. [PMID: 33803390 PMCID: PMC8005943 DOI: 10.3390/tropicalmed6010032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 11/16/2022] Open
Abstract
Cholera is a disease of poverty and occurs where there is a lack of access to clean water and adequate sanitation. Since improved water supply and sanitation infrastructure cannot be implemented immediately in many high-risk areas, vaccination against cholera is an important additional tool for prevention and control. We describe the development of licensed and recommended inactivated oral cholera vaccines (OCVs), including the results of safety, efficacy and effectiveness studies and the creation of the global OCV stockpile. Over the years, the public health strategy for oral cholera vaccination has broadened-from purely pre-emptive use to reactive deployment to help control outbreaks. Limited supplies of OCV doses continues to be an important problem. We discuss various innovative dosing and delivery approaches that have been assessed and implemented and evidence of herd protection conferred by OCVs. We expect that the demand for OCVs will continue to increase in the coming years across many countries.
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Affiliation(s)
- Jacqueline Deen
- Institute of Child Health and Human Development, National Institutes of Health, University of the Philippines, Pedro Gil Street, Ermita, Manila 1000, Philippines;
| | - John D. Clemens
- International Centre for Diarrhoeal Disease Research, GPO Box 128, Dhaka 1000, Bangladesh
- UCLA Fielding School of Public Health, 650 Charles E Young Drive South, Los Angeles, CA 90095-1772, USA
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A reactive vaccination campaign with single dose oral cholera vaccine (OCV) during a cholera outbreak in Cameroon. Vaccine 2021; 39:1290-1296. [PMID: 33494966 DOI: 10.1016/j.vaccine.2021.01.017] [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: 02/13/2020] [Revised: 11/16/2020] [Accepted: 01/04/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cameroon chose Oral Cholera Vaccine (OCV) mass vaccination campaign in addition to other interventions to respond to outbreaks since 2015. There is still a persistent controversy on the effectiveness of reactive OCV mass vaccination campaign. OBJECTIVE This article aimed to share evidence-based observations on the effect of a reactive single-dose OCV mass vaccination campaign on cholera cases in Cameroon. METHODS Health area centered risk analysis was used to identify nine high risk health areas among four health districts in the |North Region as hotspots. About 537,274 people at risk of cholera transmission one year of age and above including pregnant women were eligible to receive OCV. A total of 537,279 doses of OCV was deployed for vaccination from August 1-5, 2019 through door-to-door strategy for urban health districts, and fixed/ temporary fixed posts strategies for rural health districts. RESULTS The overall vaccination coverage was 99.9%. Vaccine wastage rate was less than 0.5% (0.0011%). Independent monitoring showed vaccination coverage at 97.2%. The 2019 epidemic curve went down after OCV intervention on the contrary to that in the year 2018 at the same period. After OCV intervention, cholera cases dropped from about 10.5 to 9.3 cases per week at the regional level while at the district level, they dropped from 5.3 to 2.1, 2.2 to 1.7, 0.6 to 0 and 1.7 to 1.5 cases per week respectively for Garoua, Garoua II, Tchollire and Pitoa. Though not statistically significant (p = 1.4, α = 0.05), cases per 1000 population seemed to remain unchanged among OCV zones (0.32/1000) and non-OCV zones (0.31/1000) in 2018 while they increased from 0.37 (OCV zones) to 0.53 (non-0CV zones) cases per 1000 population in 2019. CONCLUSION There might have been a general trend in the reduction of the number of new cases after a reactive single-dose OCV campaign.
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Jones FK, Wamala JF, Rumunu J, Mawien PN, Kol MT, Wohl S, Deng L, Pezzoli L, Omar LH, Lessler J, Quilici ML, Luquero FJ, Azman AS. Successive epidemic waves of cholera in South Sudan between 2014 and 2017: a descriptive epidemiological study. Lancet Planet Health 2020; 4:e577-e587. [PMID: 33278375 PMCID: PMC7750463 DOI: 10.1016/s2542-5196(20)30255-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 05/16/2023]
Abstract
BACKGROUND Between 2014 and 2017, successive cholera epidemics occurred in South Sudan within the context of civil war, population displacement, flooding, and drought. We aim to describe the spatiotemporal and molecular features of the three distinct epidemic waves and explore the role of vaccination campaigns, precipitation, and population movement in shaping cholera spread in this complex setting. METHODS In this descriptive epidemiological study, we analysed cholera linelist data to describe the spatiotemporal progression of the epidemics. We placed whole-genome sequence data from pandemic Vibrio cholerae collected throughout these epidemics into the global phylogenetic context. Using whole-genome sequence data in combination with other molecular attributes, we characterise the relatedness of strains circulating in each wave and the region. We investigated the association of rainfall and the instantaneous basic reproduction number using distributed lag non-linear models, compared county-level attack rates between those with early and late reactive vaccination campaigns, and explored the consistency of the spatial patterns of displacement and suspected cholera case reports. FINDINGS The 2014 (6389 cases) and 2015 (1818 cases) cholera epidemics in South Sudan remained spatially limited whereas the 2016-17 epidemic (20 438 cases) spread among settlements along the Nile river. Initial cases of each epidemic were reported in or around Juba soon after the start of the rainy season, but we found no evidence that rainfall modulated transmission during each epidemic. All isolates analysed had similar genotypic and phenotypic characteristics, closely related to sequences from Uganda and Democratic Republic of the Congo. Large-scale population movements between counties of South Sudan with cholera outbreaks were consistent with the spatial distribution of cases. 21 of 26 vaccination campaigns occurred during or after the county-level epidemic peak. Counties vaccinated on or after the peak incidence week had 2·2 times (95% CI 2·1-2·3) higher attack rates than those where vaccination occurred before the peak. INTERPRETATION Pandemic V cholerae of the same clonal origin was isolated throughout the study period despite interepidemic periods of no reported cases. Although the complex emergency in South Sudan probably shaped some of the observed spatial and temporal patterns of cases, the full scope of transmission determinants remains unclear. Timely and well targeted use of vaccines can reduce the burden of cholera; however, rapid vaccine deployment in complex emergencies remains challenging. FUNDING The Bill & Melinda Gates Foundation.
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Affiliation(s)
- Forrest K Jones
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - John Rumunu
- Republic of South Sudan Ministry of Health, Juba, South Sudan
| | | | - Mathew Tut Kol
- Republic of South Sudan Ministry of Health, Juba, South Sudan
| | - Shirlee Wohl
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Lul Deng
- Republic of South Sudan Ministry of Health, Juba, South Sudan
| | | | - Linda Haj Omar
- World Health Organization, Brazzaville, Republic of Congo
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | | | - Andrew S Azman
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Médecins Sans Frontières, Geneva, Switzerland.
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Warsame A, Murray J, Gimma A, Checchi F. The practice of evaluating epidemic response in humanitarian and low-income settings: a systematic review. BMC Med 2020; 18:315. [PMID: 33138813 PMCID: PMC7606030 DOI: 10.1186/s12916-020-01767-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/26/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Epidemics of infectious disease occur frequently in low-income and humanitarian settings and pose a serious threat to populations. However, relatively little is known about responses to these epidemics. Robust evaluations can generate evidence on response efforts and inform future improvements. This systematic review aimed to (i) identify epidemics reported in low-income and crisis settings, (ii) determine the frequency with which evaluations of responses to these epidemics were conducted, (iii) describe the main typologies of evaluations undertaken and (iv) identify key gaps and strengths of recent evaluation practice. METHODS Reported epidemics were extracted from the following sources: World Health Organization Disease Outbreak News (WHO DON), UNICEF Cholera platform, Reliefweb, PROMED and Global Incidence Map. A systematic review for evaluation reports was conducted using the MEDLINE, EMBASE, Global Health, Web of Science, WPRIM, Reliefweb, PDQ Evidence and CINAHL Plus databases, complemented by grey literature searches using Google and Google Scholar. Evaluation records were quality-scored and linked to epidemics based on time and place. The time period for the review was 2010-2019. RESULTS A total of 429 epidemics were identified, primarily in sub-Saharan Africa, the Middle East and Central Asia. A total of 15,424 potential evaluations records were screened, 699 assessed for eligibility and 132 included for narrative synthesis. Only one tenth of epidemics had a corresponding response evaluation. Overall, there was wide variability in the quality, content as well as in the disease coverage of evaluation reports. CONCLUSION The current state of evaluations of responses to these epidemics reveals large gaps in coverage and quality and bears important implications for health equity and accountability to affected populations. The limited availability of epidemic response evaluations prevents improvements to future public health response. The diversity of emphasis and methods of available evaluations limits comparison across responses and time. In order to improve future response and save lives, there is a pressing need to develop a standardized and practical approach as well as governance arrangements to ensure the systematic conduct of epidemic response evaluations in low-income and crisis settings.
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Affiliation(s)
- Abdihamid Warsame
- Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London, UK.
| | - Jillian Murray
- Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London, UK
| | - Amy Gimma
- Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London, UK
| | - Francesco Checchi
- Faculty of Epidemiology and Population Health, The London School of Hygiene & Tropical Medicine, London, UK
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Dean NE, Halloran ME, Longini IM. Temporal Confounding in the Test-Negative Design. Am J Epidemiol 2020; 189:1402-1407. [PMID: 32415834 DOI: 10.1093/aje/kwaa084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 11/15/2022] Open
Abstract
In the test-negative design, routine testing at health-care facilities is leveraged to estimate the effectiveness of an intervention such as a vaccine. The odds of vaccination for individuals who test positive for a target pathogen is compared with the odds of vaccination for individuals who test negative for that pathogen, adjusting for key confounders. The design is rapidly growing in popularity, but many open questions remain about its properties. In this paper, we examine temporal confounding by generalizing derivations to allow for time-varying vaccine status, including out-of-season controls, and open populations. We confirm that calendar time is an important confounder when vaccine status varies during the study. We demonstrate that, where time is not a confounder, including out-of-season controls can improve precision. We generalize these results to open populations. We use our theoretical findings to interpret 3 recent papers utilizing the test-negative design. Through careful examination of the theoretical properties of this study design, we provide key insights that can directly inform the implementation and analysis of future test-negative studies.
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Ratnayake R, Finger F, Azman AS, Lantagne D, Funk S, Edmunds WJ, Checchi F. Highly targeted spatiotemporal interventions against cholera epidemics, 2000-19: a scoping review. THE LANCET. INFECTIOUS DISEASES 2020; 21:e37-e48. [PMID: 33096017 DOI: 10.1016/s1473-3099(20)30479-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/27/2020] [Accepted: 05/19/2020] [Indexed: 01/12/2023]
Abstract
Globally, cholera epidemics continue to challenge disease control. Although mass campaigns covering large populations are commonly used to control cholera, spatial targeting of case households and their radius is emerging as a potentially efficient strategy. We did a Scoping Review to investigate the effectiveness of interventions delivered through case-area targeted intervention, its optimal spatiotemporal scale, and its effectiveness in reducing transmission. 53 articles were retrieved. We found that antibiotic chemoprophylaxis, point-of-use water treatment, and hygiene promotion can rapidly reduce household transmission, and single-dose vaccination can extend the duration of protection within the radius of households. Evidence supports a high-risk spatiotemporal zone of 100 m around case households, for 7 days. Two evaluations separately showed reductions in household transmission when targeting case households, and in size and duration of case clusters when targeting radii. Although case-area targeted intervention shows promise for outbreak control, it is critically dependent on early detection capacity and requires prospective evaluation of intervention packages.
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Affiliation(s)
- Ruwan Ratnayake
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | | | - Andrew S Azman
- Department of Epidemiology and Center for Humanitarian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Médecins Sans Frontières, Geneva, Switzerland
| | - Daniele Lantagne
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA, USA
| | - Sebastian Funk
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - W John Edmunds
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Francesco Checchi
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Lofano G, Mallett CP, Bertholet S, O’Hagan DT. Technological approaches to streamline vaccination schedules, progressing towards single-dose vaccines. NPJ Vaccines 2020; 5:88. [PMID: 33024579 PMCID: PMC7501859 DOI: 10.1038/s41541-020-00238-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/25/2020] [Indexed: 12/21/2022] Open
Abstract
Vaccines represent the most successful medical intervention in history, with billions of lives saved. Although multiple doses of the same vaccine are typically required to reach an adequate level of protection, it would be advantageous to develop vaccines that induce protective immunity with fewer doses, ideally just one. Single-dose vaccines would be ideal to maximize vaccination coverage, help stakeholders to greatly reduce the costs associated with vaccination, and improve patient convenience. Here we describe past attempts to develop potent single dose vaccines and explore the reasons they failed. Then, we review key immunological mechanisms of the vaccine-specific immune responses, and how innovative technologies and approaches are guiding the preclinical and clinical development of potent single-dose vaccines. By modulating the spatio-temporal delivery of the vaccine components, by providing the appropriate stimuli to the innate immunity, and by designing better antigens, the new technologies and approaches leverage our current knowledge of the immune system and may synergize to enable the rational design of next-generation vaccination strategies. This review provides a rational perspective on the possible development of future single-dose vaccines.
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Affiliation(s)
- Giuseppe Lofano
- GSK, Slaoui Center for Vaccines Research, Rockville, MD 20850 USA
| | - Corey P. Mallett
- GSK, Slaoui Center for Vaccines Research, Rockville, MD 20850 USA
| | - Sylvie Bertholet
- GSK, Slaoui Center for Vaccines Research, Rockville, MD 20850 USA
| | - Derek T. O’Hagan
- GSK, Slaoui Center for Vaccines Research, Rockville, MD 20850 USA
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Allotey P, Tan DT, Kirby T, Tan LH. Community Engagement in Support of Moving Toward Universal Health Coverage. Health Syst Reform 2020; 5:66-77. [PMID: 30924744 DOI: 10.1080/23288604.2018.1541497] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Community engagement describes a complex political process with dynamic negotiation and renegotiation of power and authority between providers and recipients of health care in order to achieve a shared goal of universal health care coverage. Though examples exist of community engagement projects, there is very little guidance on how to implement and embed community engagement as a concerted, integrated, strategic, and sustained component of health systems. Through a series of case studies, this article explores the factors that enable community engagement particularly with a direct impact on health systems.
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Affiliation(s)
- Pascale Allotey
- a UN University International Institute for Global Health UNU-IIGH , Federal Territory of Kuala Lumpur , Malaysia
| | - David T Tan
- a UN University International Institute for Global Health UNU-IIGH , Federal Territory of Kuala Lumpur , Malaysia
| | - Thomas Kirby
- a UN University International Institute for Global Health UNU-IIGH , Federal Territory of Kuala Lumpur , Malaysia
| | - Liza Haslan Tan
- a UN University International Institute for Global Health UNU-IIGH , Federal Territory of Kuala Lumpur , Malaysia
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25
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Peak CM, Stous SS, Healy JM, Hofmeister MG, Lin Y, Ramachandran S, Foster MA, Kao A, McDonald EC. Homelessness and Hepatitis A-San Diego County, 2016-2018. Clin Infect Dis 2020; 71:14-21. [PMID: 31412358 PMCID: PMC10956402 DOI: 10.1093/cid/ciz788] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 08/13/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Hepatitis A is a vaccine-preventable viral disease transmitted by the fecal-oral route. During 2016-2018, the County of San Diego investigated an outbreak of hepatitis A infections primarily among people experiencing homelessness (PEH) to identify risk factors and support control measures. At the time of the outbreak, homelessness was not recognized as an independent risk factor for the disease. METHODS We tested the association between homelessness and infection with hepatitis A virus (HAV) using a test-negative study design comparing patients with laboratory-confirmed hepatitis A with control subjects who tested negative for HAV infection. We assessed risk factors for severe hepatitis A disease outcomes, including hospitalization and death, using multivariable logistic regression. We measured the frequency of indications for hepatitis A vaccination according to Advisory Committee on Immunization Practices (ACIP) guidelines. RESULTS Among 589 outbreak-associated cases reported, 291 (49%) occurred among PEH. Compared with those who were not homeless, PEH had 3.3 (95% confidence interval [CI], 1.5-7.9) times higher odds of HAV infection, 2.5 (95% CI, 1.7-3.9) times higher odds of hospitalization, and 3.9 (95% CI, 1.1-16.9) times higher odds of death associated with hepatitis A. Among PEH, 212 (73%) patients recorded other ACIP indications for hepatitis A vaccination. CONCLUSIONS PEH were at higher risk of infection with HAV and of severe hepatitis A disease outcomes compared with those not experiencing homelessness. Approximately one-fourth of PEH had no other ACIP indication for hepatitis A vaccination. These findings support the recent ACIP recommendation to add homelessness as an indication for hepatitis A vaccination.
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Affiliation(s)
- Corey M Peak
- Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia
- County of San Diego Health and Human Services Agency, San Diego, California
- Division of Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, San Diego, California
| | - Sarah S Stous
- County of San Diego Health and Human Services Agency, San Diego, California
| | - Jessica M Healy
- Divisions of Foodborne, Waterborne, and Environmental Diseases, Atlanta, Georgia
| | - Megan G Hofmeister
- Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Yulin Lin
- Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Monique A Foster
- Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Annie Kao
- County of San Diego Health and Human Services Agency, San Diego, California
| | - Eric C McDonald
- County of San Diego Health and Human Services Agency, San Diego, California
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26
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Ngwa MC, Alemu W, Okudo I, Owili C, Ugochukwu U, Clement P, Devaux I, Pezzoli L, Oche JA, Ihekweazu C, Sack DA. The reactive vaccination campaign against cholera emergency in camps for internally displaced persons, Borno, Nigeria, 2017: a two-stage cluster survey. BMJ Glob Health 2020; 5:e002431. [PMID: 32601092 PMCID: PMC7326259 DOI: 10.1136/bmjgh-2020-002431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/20/2020] [Accepted: 05/23/2020] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION In 2017, amidst insecurity and displacements posed by Boko Haram armed insurgency, cholera outbreak started in the Muna Garage camp for Internally Displaced Persons (IDPs) in Borno State, Nigeria. In response, the Borno Ministry of Health and partners determined to provide oral cholera vaccine (OCV) to about 1 million people in IDP camps and surrounding communities in six Local Government Areas (LGAs) including Maiduguri, Jere, Konduga, Mafa, Dikwa, and Monguno. As part of Monitoring and Evaluation, we described the coverage achieved, adverse events following immunisation (AEFI), non-vaccination reasons, vaccination decisions as well as campaign information sources. METHODS We conducted two-stage probability cluster surveys with clusters selected without replacement according to probability-proportionate-to-population-size in the six LGAs targeted by the campaign. Individuals aged ≥1 years were the eligible study population. Data sources were household interviews with vaccine card verification and memory recall, if no card, as well as multiple choice questions with an open-ended option. RESULTS Overall, 12 931 respondents participated in the survey. Overall, 90% (95% CI: 88 to 92) of the target population received at least one dose of OCV, range 87% (95% CI: 75 to 94) in Maiduguri to 94% (95% CI: 88 to 97) in Monguno. The weighted two-dose coverage was 73% (95% CI: 68 to 77) with a low of 68% (95% CI: 46 to 86) in Maiduguri to a high of 87% (95% CI: 74 to 95) in Dikwa. The coverage was lower during first round (76%, 95% CI: 71 to 80) than second round (87%, 95% CI: 84 to 89) and ranged from 72% (95% CI: 42 to 89) and 82% (95% CI: 82 to 91) in Maiduguri to 87% (95% CI: 75 to 95) and 94% (95% CI: 88 to 97) in Dikwa for the respective first and second rounds. Also, coverage was higher among females of age 5 to 14 and ≥15 years than males of same age groups. There were mild AEFI with the most common symptoms being fever, headache and diarrhoea occurring up to 48 hours after ingesting the vaccine. The most common actions taken after AEFI symptoms included 'did nothing' and 'self-medicated at home'. The top reason for taking vaccine was to protect from cholera while top reason for non-vaccination was travel/work. The main source of campaign information was a neighbour. An overwhelming majority (96%, 95% CI: 95% to 98%) felt the campaign team treated them with respect. While 43% (95% CI: 36% to 50%) asked no questions, 37% (95% CI: 31% to 44%) felt the team addressed all their concerns. CONCLUSION The campaign achieved high coverage using door-to-door and fixed sites strategies amidst insecurity posed by Boko Haram. Additional studies are needed to improve how to reduce non-vaccination, especially for the first round. While OCV provides protection for a few years, additional actions will be needed to make investments in water, sanitation and hygiene infrastructure.
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Affiliation(s)
- Moise Chi Ngwa
- International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | | | | | | | | | | | | | | | | | - David A Sack
- International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
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27
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Meteke S, Stefopulos M, Als D, Gaffey M, Kamali M, Siddiqui FJ, Munyuzangabo M, Jain RP, Shah S, Radhakrishnan A, Ataullahjan A, Bhutta ZA. Delivering infectious disease interventions to women and children in conflict settings: a systematic reviefw. BMJ Glob Health 2020; 5:e001967. [PMID: 32341087 PMCID: PMC7213813 DOI: 10.1136/bmjgh-2019-001967] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 02/19/2020] [Accepted: 03/07/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Conflict has played a role in the large-scale deterioration of health systems in low-income and middle-income countries (LMICs) and increased risk of infections and outbreaks. This systematic review aimed to synthesise the literature on mechanisms of delivery for a range of infectious disease-related interventions provided to conflict-affected women, children and adolescents. METHODS We searched Medline, Embase, CINAHL and PsychINFO databases for literature published in English from January 1990 to March 2018. Eligible publications reported on conflict-affected neonates, children, adolescents or women in LMICs who received an infectious disease intervention. We extracted and synthesised information on delivery characteristics, including delivery site and personnel involved, as well as barriers and facilitators, and we tabulated reported intervention coverage and effectiveness data. RESULTS A majority of the 194 eligible publications reported on intervention delivery in sub-Saharan Africa. Vaccines for measles and polio were the most commonly reported interventions, followed by malaria treatment. Over two-thirds of reported interventions were delivered in camp settings for displaced families. The use of clinics as a delivery site was reported across all intervention types, but outreach and community-based delivery were also reported for many interventions. Key barriers to service delivery included restricted access to target populations; conversely, adopting social mobilisation strategies and collaborating with community figures were reported as facilitating intervention delivery. Few publications reported on intervention coverage, mostly reporting variable coverage for vaccines, and fewer reported on intervention effectiveness, mostly for malaria treatment regimens. CONCLUSIONS Despite an increased focus on health outcomes in humanitarian crises, our review highlights important gaps in the literature on intervention delivery among specific subpopulations and geographies. This indicates a need for more rigorous research and reporting on effective strategies for delivering infectious disease interventions in different conflict contexts. PROSPERO REGISTRATION NUMBER CRD42019125221.
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Affiliation(s)
- Sarah Meteke
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Marianne Stefopulos
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Daina Als
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michelle Gaffey
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mahdis Kamali
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Fahad J Siddiqui
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Health System and Services Research, Duke-NUS Medical School, Singapore
| | - Mariella Munyuzangabo
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Reena P Jain
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shailja Shah
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Amruta Radhakrishnan
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anushka Ataullahjan
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zulfiqar A Bhutta
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Center of Excellence in Women and Child Health, Aga Khan University, Karachi, Pakistan
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Alternative observational designs to estimate the effectiveness of one dose of oral cholera vaccine in Lusaka, Zambia. Epidemiol Infect 2020; 148:e78. [PMID: 32167038 PMCID: PMC7163804 DOI: 10.1017/s095026882000062x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We conducted a matched case-control (MCC), test-negative case-control (TNCC) and case-cohort study in 2016 in Lusaka, Zambia, following a mass vaccination campaign. Confirmed cholera cases served as cases in all three study designs. In the TNCC, control-subjects were cases with negative cholera culture and polymerase chain reaction results. Matched controls by age and sex were selected among neighbours of the confirmed cases in the MCC study. For the case-cohort study, we recruited a cohort of randomly selected individuals living in areas considered at-risk of cholera. We recruited 211 suspected cases (66 confirmed cholera cases and 145 non-cholera diarrhoea cases), 1055 matched controls and a cohort of 921. Adjusted vaccine effectiveness of one dose of oral cholera vaccine (OCV) was 88.9% (95% confidence interval (CI) 42.7–97.8) in the MCC study, 80.2% (95% CI: 16.9–95.3) in the TNCC design and 89.4% (95% CI: 64.6–96.9) in the case-cohort study. Three study designs confirmed the short-term effectiveness of single dose OCV. Major healthcare-seeking behaviour bias did not appear to affect our estimates. Most of the protection among vaccinated individuals could be attributed to the direct effect of the vaccine.
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Kahn R, Peak CM, Fernández-Gracia J, Hill A, Jambai A, Ganda L, Castro MC, Buckee CO. Incubation periods impact the spatial predictability of cholera and Ebola outbreaks in Sierra Leone. Proc Natl Acad Sci U S A 2020; 117:5067-5073. [PMID: 32054785 PMCID: PMC7060667 DOI: 10.1073/pnas.1913052117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Forecasting the spatiotemporal spread of infectious diseases during an outbreak is an important component of epidemic response. However, it remains challenging both methodologically and with respect to data requirements, as disease spread is influenced by numerous factors, including the pathogen's underlying transmission parameters and epidemiological dynamics, social networks and population connectivity, and environmental conditions. Here, using data from Sierra Leone, we analyze the spatiotemporal dynamics of recent cholera and Ebola outbreaks and compare and contrast the spread of these two pathogens in the same population. We develop a simulation model of the spatial spread of an epidemic in order to examine the impact of a pathogen's incubation period on the dynamics of spread and the predictability of outbreaks. We find that differences in the incubation period alone can determine the limits of predictability for diseases with different natural history, both empirically and in our simulations. Our results show that diseases with longer incubation periods, such as Ebola, where infected individuals can travel farther before becoming infectious, result in more long-distance sparking events and less predictable disease trajectories, as compared to the more predictable wave-like spread of diseases with shorter incubation periods, such as cholera.
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Affiliation(s)
- Rebecca Kahn
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Corey M Peak
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Juan Fernández-Gracia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115
- Institute for Cross-Disciplinary Physics and Complex Systems, Universitat de les Illes Balears - Consell Superior d'Investigacions Científiques, E-07122 Palma de Mallorca, Spain
| | - Alexandra Hill
- Disease Control in Humanitarian Emergencies, World Health Organization, CH-1211 Geneva 27, Switzerland
| | - Amara Jambai
- Disease Control and Prevention, Sierra Leone Ministry of Health and Sanitation, Freetown, Sierra Leone FPGG+89
| | - Louisa Ganda
- Country Office, World Health Organization, Freetown, Sierra Leone FPGG+89
| | - Marcia C Castro
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Caroline O Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115;
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Emergence of Haitian variant genotype and altered drug susceptibility in Vibrio cholerae O1 El Tor-associated cholera outbreaks in Solapur, India. Int J Antimicrob Agents 2020; 55:105853. [DOI: 10.1016/j.ijantimicag.2019.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/12/2019] [Accepted: 11/13/2019] [Indexed: 11/23/2022]
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Pezzoli L. Global oral cholera vaccine use, 2013-2018. Vaccine 2020; 38 Suppl 1:A132-A140. [PMID: 31519444 PMCID: PMC10967685 DOI: 10.1016/j.vaccine.2019.08.086] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/01/2019] [Accepted: 08/30/2019] [Indexed: 12/17/2022]
Abstract
Vaccination is a key intervention to prevent and control cholera in conjunction with water, sanitation and hygiene activities. An oral cholera vaccine (OCV) stockpile was established by the World Health Organization (WHO) in 2013. We reviewed its use from July 2013 to all of 2018 in order to assess its role in cholera control. We computed information related to OCV deployments and campaigns conducted including setting, target population, timelines, delivery strategy, reported adverse events, coverage achieved, and costs. In 2013-2018, a total of 83,509,941 OCV doses have been requested by 24 countries, of which 55,409,160 were approved and 36,066,010 eventually shipped in 83 deployments, resulting in 104 vaccination campaigns in 22 countries. OCVs had in general high uptake (mean administrative coverage 1st dose campaign at 90.3%; 2nd dose campaign at 88.2%; mean survey-estimated two-dose coverage at 69.9%, at least one dose at 84.6%) No serious adverse events were reported. Campaigns were organized quickly (five days median duration). In emergency settings, the longest delay was from the occurrence of the emergency to requesting OCV (median: 26 days). The mean cost of administering one dose of vaccine was 2.98 USD. The OCV stockpile is an important public health resource. OCVs were generally well accepted by the population and their use demonstrated to be safe and feasible in all settings. OCV was an inexpensive intervention, although timing was a limiting factor for emergency use. The dynamic created by the establishment of the OCV stockpile has played a role in the increased use of the vaccine by setting in motion a virtuous cycle by which better monitoring and evaluation leads to better campaign organization, better cholera control, and more requests being generated. Further work is needed to improve timeliness of response and contextualize strategies for OCV delivery in the various settings.
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Affiliation(s)
- Lorenzo Pezzoli
- Cholera Team/Focal Point for Vaccination, Infectious Hazard Management (IHM), World Health Organization, Switzerland
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Can cholera 'hotspots' be converted to cholera 'coldspots' in cholera endemic countries? The Matlab, Bangladesh experience. Int J Infect Dis 2020; 95:28-31. [PMID: 32126325 PMCID: PMC7294221 DOI: 10.1016/j.ijid.2020.02.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 11/24/2022] Open
Abstract
Matlab, Bangladesh was a well-documented cholera ‘hotspot’ – an area of regularly recurrent cholera with a high annual incidence – for many decades. In recent years, cholera has declined to negligible levels in Matlab, despite persistently high rates in many areas of Bangladesh and despite increasing local ambient and sea surface temperatures, which favor a high cholera incidence. The decline occurred following the provision of low-cost tubewells for the supply of water and inexpensive sanitary latrines to a high proportion of the population. These observations lend optimism to the success of the World Health Organization current global initiative to end preventable cholera by 2030.
Background Cholera remains a major public health threat in low- and middle-income countries. The World Health Organization (WHO) has recently launched a global initiative to end preventable cholera by 2030. Key to the success of this initiative will be the elimination of cholera transmission in cholera ‘hotspots’ with regularly recurrent disease; this can be achieved via improved surveillance to define hotspot populations, through the use of oral cholera vaccines, and through the implementation of improved water, sanitation, and hygiene (WASH). Methods This study was performed to analyze the trend in cholera incidence during the years 1974–2018 in Matlab, Bangladesh (defined population of about 200 000) that has been recognized as one of the world’s cholera hotspots. During this period, Matlab has maintained a demographically defined population and comprehensive, culture-based surveillance for cholera, supplemented by periodic surveys to characterize the socioeconomic status of the population, as well as water sources and facilities for defecation. Results Cholera transmission has nearly been eliminated in Matlab, despite a continuing high cholera burden in many other parts of Bangladesh and despite trends of increasing ambient and sea surface temperatures, which are known to increase cholera incidence. Concomitantly, the socioeconomic status of the population has increased modestly, and the use of simple tubewells for drinking water has reached 95% and the installation of sanitary latrines has reached 85%. Conclusions The factors responsible for the decline in cholera are difficult to pinpoint precisely, but this decline has occurred with the installation of inexpensive improvements in water sources and latrines and despite environmental factors that should have augmented cholera incidence. These observations lend optimism to the current global initiative to end preventable cholera by 2030.
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Panda S, Chatterjee P, Deb A, Kanungo S, Dutta S. Preventing cholera in India: Synthesizing evidences through a systematic review for policy discussion on the use of oral cholera vaccine. Vaccine 2020; 38 Suppl 1:A148-A156. [DOI: 10.1016/j.vaccine.2019.07.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/30/2019] [Accepted: 07/05/2019] [Indexed: 01/28/2023]
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Ngwa MC, Wondimagegnehu A, Okudo I, Owili C, Ugochukwu U, Clement P, Devaux I, Pezzoli L, Ihekweazu C, Jimme MA, Winch P, Sack DA. The multi-sectorial emergency response to a cholera outbreak in Internally Displaced Persons camps in Borno State, Nigeria, 2017. BMJ Glob Health 2020; 5:e002000. [PMID: 32133173 PMCID: PMC7042583 DOI: 10.1136/bmjgh-2019-002000] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 01/24/2023] Open
Abstract
Introduction In August 2017, a cholera outbreak started in Muna Garage Internally Displaced Persons camp, Borno state, Nigeria and >5000 cases occurred in six local government areas. This qualitative study evaluated perspectives about the emergency response to this outbreak. Methods We conducted 39 key informant interviews and focus group discussions, and reviewed 21 documents with participants involved with surveillance, water, sanitation, hygiene, case management, oral cholera vaccine (OCV), communications, logistics and coordination. Qualitative data analysis used thematic techniques comprising key words in context, word repetition and key sector terms. Results Authorities were alerted quickly, but outbreak declaration took 12 days due to a 10-day delay waiting for culture confirmation. Outbreak investigation revealed several potential transmission channels, but a leaking latrine around the index cases’ house was not repaired for more than 7 days. Chlorine was initially not accepted by the community due to rumours that it would sterilise women. Key messages were in Hausa, although Kanuri was the primary local language; later this was corrected. Planning would have benefited using exercise drills to identify weaknesses, and inventory sharing to avoid stock outs. The response by the Rural Water Supply and Sanitation Agency was perceived to be slow and an increased risk from a religious festival was not recognised. Case management was provided at treatment centres, but some partners were concerned that their work was not recognised asking, ‘Who gets the glory and the data?’ Nearly one million people received OCV and its distribution benefited from a robust infrastructure for polio vaccination. There was initial anxiety, rumour and reluctance about OCV, attributed by many to lack of formative research prior to vaccine implementation. Coordination was slow initially, but improved with activation of an emergency operations centre (EOC) that enabled implementation of incident management system to coordinate multisectoral activities and meetings held at 16:00 hours daily. The synergy between partners and government improved when each recognised the government’s leadership role. Conclusion Despite a timely alert of the outbreak, delayed laboratory confirmation slowed initial response. Initial responses to the outbreak were not well coordinated but improved with the EOC. Understanding behaviours and community norms through rapid formative research should improve the effectiveness of the emergency response to a cholera outbreak. OCV distribution was efficient and benefited from the polio vaccine infrastructure.
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Affiliation(s)
- Moise Chi Ngwa
- International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | - Ifeanyi Okudo
- World Health Organisation, Nigeria Country Office, Abuja, Nigeria
| | - Collins Owili
- World Health Organisation, Nigeria Country Office, Abuja, Nigeria
| | - Uzoma Ugochukwu
- World Health Organisation, Nigeria Country Office, Abuja, Nigeria
| | - Peter Clement
- World Health Organisation, Nigeria Country Office, Abuja, Nigeria
| | | | | | | | - Mohammed Abba Jimme
- Geography, University of Maiduguri Faculty of Social Science, Maiduguri, Nigeria
| | - Peter Winch
- International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - David A Sack
- International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
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Roskosky M, Acharya B, Shakya G, Karki K, Sekine K, Bajracharya D, von Seidlein L, Devaux I, Lopez AL, Deen J, Sack DA. Feasibility of a Comprehensive Targeted Cholera Intervention in The Kathmandu Valley, Nepal. Am J Trop Med Hyg 2020; 100:1088-1097. [PMID: 30887946 PMCID: PMC6493959 DOI: 10.4269/ajtmh.18-0863] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A comprehensive targeted intervention (CTI) was designed and deployed in the neighborhoods of cholera cases in the Kathmandu Valley with the intent of reducing rates among the neighbors of the case. This was a feasibility study to determine whether clinical centers, laboratories, and field teams were able to mount a rapid, community-based response to a case within 2 days of hospital admission. Daily line listings were requested from 15 participating hospitals during the monsoon season, and a single case initiated the CTI. A standard case definition was used: acute watery diarrhea, with or without vomiting, in a patient aged 1 year or older. Rapid diagnostic tests and bacterial culture were used for confirmation. The strategy included household investigation of cases; water testing; water, sanitation, and hygiene (WASH) intervention; and health education. A CTI coverage survey was conducted 8 months postintervention. From June to December of 2016, 169 cases of Vibrio cholerae O1 were confirmed by bacterial culture. Average time to culture result was 3 days. On average, the CTI Rapid Response Team (RRT) was able to visit households 1.7 days after the culture result was received from the hospital (3.9 days from hospital admission). Coverage of WASH and health behavior messaging campaigns were 30.2% in the target areas. Recipients of the intervention were more likely to have knowledge of cholera symptoms, treatment, and prevention than non-recipients. Although the RRT were able to investigate cases at the household within 2 days of a positive culture result, the study identified several constraints that limited a truly rapid response.
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Affiliation(s)
- Mellisa Roskosky
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Bhim Acharya
- Epidemiology Disease Control Division, Department of Health Services, Ministry of Health, Kathmandu, Nepal
| | - Geeta Shakya
- National Public Health Laboratory, Department of Health Services, Ministry of Health, Kathmandu, Nepal
| | | | - Kazutaka Sekine
- United Nations International Children's Emergency Fund (UNICEF) Sierra Leone, Freetown, Sierra Leone
| | | | - Lorenz von Seidlein
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom.,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Isabelle Devaux
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Anna Lena Lopez
- Institute of Child Health and Human Development, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Jacqueline Deen
- Institute of Child Health and Human Development, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - David A Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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Lubogo M, Mohamed AM, Ali AH, Ali AH, Popal GR, Kiongo D, Bile KM, Malik M, Abubakar A. Oral cholera vaccination coverage in an acute emergency setting in Somalia, 2017. Vaccine 2020; 38 Suppl 1:A141-A147. [PMID: 31980193 DOI: 10.1016/j.vaccine.2020.01.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 11/09/2019] [Accepted: 01/07/2020] [Indexed: 10/25/2022]
Abstract
The first oral cholera vaccination (OCV) campaign in Somalia was implemented between March and October 2017. It was the first time the Ministry of Health had introduced and used OCV as part of the cholera prevention and control strategies. The Ministry of Health aimed to cover 1.1 million people ≥ 1 year with 2 doses of the OCV in 11 high-risk districts. Overall, 2-dose administrative OCV coverage in all targeted districts was 95.5%. Following the campaign, a random sample survey was conducted in 9 out of 11districts to evaluate coverage, awareness, reasons for non-vaccination, the water and sanitation status of households, and any resulting adverse events. The survey was conducted in 2 phases. Of the 3,715 eligible individuals in the first phase, 92.5% (95% CI 91.4-93.6%) received 2 doses of the OCV and 7.0% (95% CI 6.0-8.2%) 1 dose. In the second phase, of 1,926 individuals, 94.1% (95% CI 92.9-95.1%) received 2 doses and 2.6% (95% CI 2.0-3.4%) 1 dose. Despite challenges, this experience shows that OCV campaigns can be implemented in acute humanitarian settings through existing immunization structures.
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Affiliation(s)
- Mutaawe Lubogo
- World Health Organization, Somalia Country Office, Mogadishu, Somalia
| | | | | | - Aden H Ali
- Federal Ministry of Health, Mogadishu, Somalia
| | - Ghulam R Popal
- World Health Organization, Somalia Country Office, Mogadishu, Somalia
| | - David Kiongo
- Independent Monitoring and Evaluation Consultant, Nairobi, Kenya
| | | | - Mamunur Malik
- World Health Organization Eastern Mediterranean Region, Cairo, Egypt
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Prevention and control of cholera with household and community water, sanitation and hygiene (WASH) interventions: A scoping review of current international guidelines. PLoS One 2020; 15:e0226549. [PMID: 31914164 PMCID: PMC6948749 DOI: 10.1371/journal.pone.0226549] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/03/2019] [Indexed: 12/13/2022] Open
Abstract
Introduction Cholera remains a frequent cause of outbreaks globally, particularly in areas with inadequate water, sanitation and hygiene (WASH) services. Cholera is spread through faecal-oral routes, and studies demonstrate that ingestion of Vibrio cholerae occurs from consuming contaminated food and water, contact with cholera cases and transmission from contaminated environmental point sources. WASH guidelines recommending interventions for the prevention and control of cholera are numerous and vary considerably in their recommendations. To date, there has been no review of practice guidelines used in cholera prevention and control programmes. Methods We systematically searched international agency websites to identify WASH intervention guidelines used in cholera programmes in endemic and epidemic settings. Recommendations listed in the guidelines were extracted, categorised and analysed. Analysis was based on consistency, concordance and recommendations were classified on the basis of whether the interventions targeted within-household or community-level transmission. Results Eight international guidelines were included in this review: three by non-governmental organisations (NGOs), one from a non-profit organisation (NPO), three from multilateral organisations and one from a research institution. There were 95 distinct recommendations identified, and concordance among guidelines was poor to fair. All categories of WASH interventions were featured in the guidelines. The majority of recommendations targeted community-level transmission (45%), 35% targeted within-household transmission and 20% both. Conclusions Recent evidence suggests that interventions for effective cholera control and response to epidemics should focus on case-centred approaches and within-household transmission. Guidelines did consistently propose interventions targeting transmission within households. However, the majority of recommendations listed in guidelines targeted community-level transmission and tended to be more focused on preventing contamination of the environment by cases or recurrent outbreaks, and the level of service required to interrupt community-level transmission was often not specified. The guidelines in current use were varied and interpretation may be difficult when conflicting recommendations are provided. Future editions of guidelines should reflect on the inclusion of evidence-based approaches, cholera transmission models and resource-efficient strategies.
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Chua H, Feng S, Lewnard JA, Sullivan SG, Blyth CC, Lipsitch M, Cowling BJ. The Use of Test-negative Controls to Monitor Vaccine Effectiveness: A Systematic Review of Methodology. Epidemiology 2020; 31:43-64. [PMID: 31609860 PMCID: PMC6888869 DOI: 10.1097/ede.0000000000001116] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The test-negative design is an increasingly popular approach for estimating vaccine effectiveness (VE) due to its efficiency. This review aims to examine published test-negative design studies of VE and to explore similarities and differences in methodological choices for different diseases and vaccines. METHODS We conducted a systematic search on PubMed, Web of Science, and Medline, for studies reporting the effectiveness of any vaccines using a test-negative design. We screened titles and abstracts and reviewed full texts to identify relevant articles. We created a standardized form for each included article to extract information on the pathogen of interest, vaccine(s) being evaluated, study setting, clinical case definition, choices of cases and controls, and statistical approaches used to estimate VE. RESULTS We identified a total of 348 articles, including studies on VE against influenza virus (n = 253), rotavirus (n = 48), pneumococcus (n = 24), and nine other pathogens. Clinical case definitions used to enroll patients were similar by pathogens of interest but the sets of symptoms that defined them varied substantially. Controls could be those testing negative for the pathogen of interest, those testing positive for nonvaccine type of the pathogen of interest, or a subset of those testing positive for alternative pathogens. Most studies controlled for age, calendar time, and comorbidities. CONCLUSIONS Our review highlights similarities and differences in the application of the test-negative design that deserve further examination. If vaccination reduces disease severity in breakthrough infections, particular care must be taken in interpreting vaccine effectiveness estimates from test-negative design studies.
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Affiliation(s)
- Huiying Chua
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shuo Feng
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Joseph A Lewnard
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA
| | - Sheena G Sullivan
- WHO Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, and Doherty Department, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher C Blyth
- Division of Paediatrics, School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, Western Australia, Australia
- Department of Infectious Diseases, Perth Children's Hospital, Perth, Western Australia, Australia
| | - Marc Lipsitch
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA
- Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Benjamin J Cowling
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
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Chatterjee P, Kanungo S, Bhattacharya SK, Dutta S. Mapping cholera outbreaks and antibiotic resistant Vibrio cholerae in India: An assessment of existing data and a scoping review of the literature. Vaccine 2019; 38 Suppl 1:A93-A104. [PMID: 31883807 DOI: 10.1016/j.vaccine.2019.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 10/18/2019] [Accepted: 12/03/2019] [Indexed: 12/18/2022]
Abstract
Although fluid and electrolyte replenishment remains the mainstay of clinical management of cholera, antibiotics are an important component of the strategy for clinical management of moderate to severe cases of cholera. The emergence of antibiotic resistance (ABR) in Vibrio cholerae has led to difficulties in case management. The past decade has also seen the development of cheap and effective oral cholera vaccines (OCVs). In addition to the two-dose strategy for widespread immunization, OCVs have also been shown to be effective in containing outbreaks using a single-dose schedule. In this scoping review we map the states and union territories (SUTs) of India which are prone to cholera outbreaks followed by a scoping review of peer-reviewed publications about ABR outbreaks of cholera employing the Arksey and O'Malley framework. Using the data reported by the Integrated Disease Surveillance Program (IDSP), we identified 559 outbreaks of cholera between 2009 and 2017, affecting 27 SUTs. We defined SUTs which had reported outbreaks in at least three out of the last five years (2012-2016) or had experienced two or more outbreaks in the same year in at least two of the last five years to be outbreak-prone. The scoping review identified 62 ABR outbreaks, with four SUTs accounting for two-thirds of them: West Bengal (14), Maharashtra (10), Odisha (10) and Delhi (7). Overall, this scoping review suggests that there is an increasing trend of ABR in Vibrio cholerae isolated from outbreaks in India. This opens up avenues for exploring the role of antibiotic stewardship in the clinical management of diarrhea, the institution of vaccination as an infection prevention intervention to reduce selection pressure, and the deployment of high quality surveillance systems which report accurate, real-time data allowing appropriate and timely public health responses. It is crucial to counter the issue of ABR in cholera before it assumes a menacing magnitude.
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Affiliation(s)
- Pranab Chatterjee
- Division of Epidemiology, Indian Council of Medical Research, National Institute of Cholera and Enteric Diseases, Kolkata, India.
| | - Suman Kanungo
- Division of Epidemiology, Indian Council of Medical Research, National Institute of Cholera and Enteric Diseases, Kolkata, India.
| | | | - Shanta Dutta
- Division of Bacteriology, Indian Council of Medical Research, National Institute of Cholera and Enteric Diseases, India
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Havumaki J, Meza R, Phares CR, Date K, Eisenberg MC. Comparing alternative cholera vaccination strategies in Maela refugee camp: using a transmission model in public health practice. BMC Infect Dis 2019; 19:1075. [PMID: 31864298 PMCID: PMC6925891 DOI: 10.1186/s12879-019-4688-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/08/2019] [Indexed: 12/11/2022] Open
Abstract
Background Cholera is a major public health concern in displaced-person camps, which often contend with overcrowding and scarcity of resources. Maela, the largest and longest-standing refugee camp in Thailand, located along the Thai-Burmese border, experienced four cholera outbreaks between 2005 and 2010. In 2013, a cholera vaccine campaign was implemented in the camp. To assist in the evaluation of the campaign and planning for subsequent campaigns, we developed a mathematical model of cholera in Maela. Methods We formulated a Susceptible-Infectious-Water-Recovered-based transmission model and estimated parameters using incidence data from 2010. We next evaluated the reduction in cases conferred by several immunization strategies, varying timing, effectiveness, and resources (i.e., vaccine availability). After the vaccine campaign, we generated case forecasts for the next year, to inform on-the-ground decision-making regarding whether a booster campaign was needed. Results We found that preexposure vaccination can substantially reduce the risk of cholera even when <50% of the population is given the full two-dose series. Additionally, the preferred number of doses per person should be considered in the context of one vs. two dose effectiveness and vaccine availability. For reactive vaccination, a trade-off between timing and effectiveness was revealed, indicating that it may be beneficial to give one dose to more people rather than two doses to fewer people, given that a two-dose schedule would incur a delay in administration of the second dose. Forecasting using realistic coverage levels predicted that there was no need for a booster campaign in 2014 (consistent with our predictions, there was not a cholera epidemic in 2014). Conclusions Our analyses suggest that vaccination in conjunction with ongoing water sanitation and hygiene efforts provides an effective strategy for controlling cholera outbreaks in refugee camps. Effective preexposure vaccination depends on timing and effectiveness. If a camp is facing an outbreak, delayed distribution of vaccines can substantially alter the effectiveness of reactive vaccination, suggesting that quick distribution of vaccines may be more important than ensuring every individual receives both vaccine doses. Overall, this analysis illustrates how mathematical models can be applied in public health practice, to assist in evaluating alternative intervention strategies and inform decision-making.
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Affiliation(s)
- Joshua Havumaki
- Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, USA
| | - Rafael Meza
- Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, USA
| | - Christina R Phares
- US Centers for Disease Control and Prevention; National Center for Emerging and Zoonotic Infectious Diseases; Division of Global Migration and Quarantine and Prevention, 1600 Clifton Road, Atlanta, 30329, GA, USA
| | - Kashmira Date
- US Centers for Disease Control and Prevention; Global Immunization Division - Center for Global Health, 1600 Clifton Road, Atlanta, 30329, GA, USA
| | - Marisa C Eisenberg
- Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, USA.
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Lee EC, Azman AS, Kaminsky J, Moore SM, McKay HS, Lessler J. The projected impact of geographic targeting of oral cholera vaccination in sub-Saharan Africa: A modeling study. PLoS Med 2019; 16:e1003003. [PMID: 31825965 PMCID: PMC6905526 DOI: 10.1371/journal.pmed.1003003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 11/15/2019] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Cholera causes an estimated 100,000 deaths annually worldwide, with the majority of burden reported in sub-Saharan Africa. In May 2018, the World Health Assembly committed to reducing worldwide cholera deaths by 90% by 2030. Oral cholera vaccine (OCV) plays a key role in reducing the near-term risk of cholera, although global supplies are limited. Characterizing the potential impact and cost-effectiveness of mass OCV deployment strategies is critical for setting expectations and developing cholera control plans that maximize the chances of success. METHODS AND FINDINGS We compared the projected impacts of vaccination campaigns across sub-Saharan Africa from 2018 through 2030 when targeting geographically according to historical cholera burden and risk factors. We assessed the number of averted cases, deaths, and disability-adjusted life years and the cost-effectiveness of these campaigns with models that accounted for direct and indirect vaccine effects and population projections over time. Under current vaccine supply projections, an approach optimized to targeting by historical burden is projected to avert 828,971 (95% CI 803,370-859,980) cases (equivalent to 34.0% of projected cases; 95% CI 33.2%-34.8%). An approach that balances logistical feasibility with targeting historical burden is projected to avert 617,424 (95% CI 599,150-643,891) cases. In contrast, approaches optimized for targeting locations with limited access to water and sanitation are projected to avert 273,939 (95% CI 270,319-277,002) and 109,817 (95% CI 103,735-114,110) cases, respectively. We find that the most logistically feasible targeting strategy costs US$1,843 (95% CI 1,328-14,312) per DALY averted during this period and that effective geographic targeting of OCV campaigns can have a greater impact on cost-effectiveness than improvements to vaccine efficacy and moderate increases in coverage. Although our modeling approach does not project annual changes in baseline cholera risk or directly incorporate immunity from natural cholera infection, our estimates of the relative performance of different vaccination strategies should be robust to these factors. CONCLUSIONS Our study suggests that geographic targeting substantially improves the cost-effectiveness and impact of oral cholera vaccination campaigns. Districts with the poorest access to improved water and sanitation are not the same as districts with the greatest historical cholera incidence. While OCV campaigns can improve cholera control in the near term, without rapid progress in developing water and sanitation services or dramatic increases in OCV supply, our results suggest that vaccine use alone is unlikely to allow us to achieve the 2030 goal.
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Affiliation(s)
- Elizabeth C. Lee
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
| | - Andrew S. Azman
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Joshua Kaminsky
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Sean M. Moore
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Heather S. McKay
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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Chen WH, Azman AS. Mitigating Cholera in the Aftermath of Cyclone Idai. Am J Trop Med Hyg 2019; 101:960-962. [PMID: 31333158 PMCID: PMC6838597 DOI: 10.4269/ajtmh.19-0285] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/21/2019] [Indexed: 01/30/2023] Open
Abstract
Catastrophic damage and floods followed the deadliest cyclone on record for the Southern Hemisphere. In the aftermath of Cyclone Idai, a cholera outbreak was detected. The global stockpile of oral cholera vaccine was rapidly deployed to counter this fast-growing epidemic. We urge the international community to continue to highlight the importance of water, sanitation, and hygiene as the long-term goal for controlling cholera and meeting the 2030 Sustainable Development Goals.
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Affiliation(s)
- Wilbur H. Chen
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrew S. Azman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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Ciglenecki I, Azman AS, Jamet C, Serafini M, Luquero FJ, Cabrol JC. Progress and Challenges in Using Oral Cholera Vaccines to Control Outbreaks: The Médecins Sans Frontières Experience. J Infect Dis 2019; 218:S165-S166. [PMID: 30239901 PMCID: PMC6188544 DOI: 10.1093/infdis/jiy487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The use of oral cholera vaccine (OCV) has increased since 2011, when Shanchol, the first OCV suitable for large-scale use, became available. Médecins Sans Frontières considers OCVs an essential cholera outbreak control tool and has contributed to generating new evidence on OCV use in outbreaks. We showed that large-scale mass campaigns are feasible during outbreaks, documented high short-term effectiveness and showed that vaccines are likely safe in pregnancy. We found that a single-dose regimen has high short-term effectiveness, making rapid delivery of vaccine during outbreaks easier, especially given the on-going global vaccine shortage. Despite progress, OCV has still not been used widely in some of the largest recent outbreaks and thousands of cholera deaths are reported every year. While working towards improving our tools to protect those most at-risk of cholera, we must strive to use all available effective interventions in efficient ways, including OCV, to prevent avoidable deaths today.
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Affiliation(s)
| | - Andrew S Azman
- Médecins Sans Frontières, Geneva, Switzerland.,Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland
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Ferreras E, Matapo B, Chizema-Kawesha E, Chewe O, Mzyece H, Blake A, Moonde L, Zulu G, Poncin M, Sinyange N, Kasese-Chanda N, Phiri C, Malama K, Mukonka V, Cohuet S, Uzzeni F, Ciglenecki I, Danovaro-Holliday MC, Luquero FJ, Pezzoli L. Delayed second dose of oral cholera vaccine administered before high-risk period for cholera transmission: Cholera control strategy in Lusaka, 2016. PLoS One 2019; 14:e0219040. [PMID: 31469853 PMCID: PMC6716633 DOI: 10.1371/journal.pone.0219040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/16/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In April 2016, an emergency vaccination campaign using one dose of Oral Cholera Vaccine (OCV) was organized in response to a cholera outbreak that started in Lusaka in February 2016. In December 2016, a second round of vaccination was conducted, with the objective of increasing the duration of protection, before the high-risk period for cholera transmission. We assessed vaccination coverage for the first and second rounds of the OCV campaign. METHODS Vaccination coverage was estimated after each round from a sample selected from targeted-areas for vaccination using a cross-sectional survey in to establish the vaccination status of the individuals recruited. The study population included all individuals older than 12 months residing in the areas targeted for vaccination. We interviewed 505 randomly selected individuals after the first round and 442 after the second round. Vaccination status was ascertained either by vaccination card or verbal reporting. Households were selected using spatial random sampling. RESULTS The vaccination coverage with two doses was 58.1% (25/43; 95%CI: 42.1-72.9) in children 1-5 years old, 59.5% (69/116; 95%CI: 49.9-68.5) in children 5-15 years old and 19.9% (56/281; 95%CI: 15.4-25.1) in adults above 15 years old. The overall dropout rate was 10.9% (95%CI: 8.1-14.1). Overall, 69.9% (n = 309/442; 95%CI: 65.4-74.1) reported to have received at least one OCV dose. CONCLUSIONS The areas at highest risk of suffering cholera outbreaks were targeted for vaccination obtaining relatively high vaccine coverage after each round. However, the long delay between doses in areas subject to considerable population movement resulted in many individuals receiving only one OCV dose. Additional vaccination campaigns may be required to sustain protection over time in case of persistence of risk. Further evidence is needed to establish a maximum optimal interval time of a delayed second dose and variations in different settings.
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Affiliation(s)
- Eva Ferreras
- World Health Organization, Lusaka, Zambia
- Epicentre, Paris, France
| | | | | | - Orbrie Chewe
- Ministry of Health, Lusaka, Zambia
- Zambia National Public Health Institute, Lusaka, Zambia
| | - Hannah Mzyece
- Ministry of Health, Lusaka, Zambia
- Zambia National Public Health Institute, Lusaka, Zambia
| | | | | | | | - Marc Poncin
- Médecins Sans Frontières, Geneva, Switzerland
| | - Nyambe Sinyange
- Ministry of Health, Lusaka, Zambia
- Zambia National Public Health Institute, Lusaka, Zambia
| | | | | | | | | | | | | | | | | | - Francisco J. Luquero
- Epicentre, Paris, France
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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Ainslie KEC, Haber M, Orenstein WA. Challenges in estimating influenza vaccine effectiveness. Expert Rev Vaccines 2019; 18:615-628. [PMID: 31116070 PMCID: PMC6594904 DOI: 10.1080/14760584.2019.1622419] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/20/2019] [Indexed: 12/25/2022]
Abstract
Introduction: Influenza vaccination is regarded as the most effective way to prevent influenza infection. Due to the rapid genetic changes that influenza viruses undergo, seasonal influenza vaccines must be reformulated and re-administered annually necessitating the evaluation of influenza vaccine effectiveness (VE) each year. The estimation of influenza VE presents numerous challenges. Areas Covered: This review aims to identify, discuss, and, where possible, offer suggestions for dealing with the following challenges in estimating influenza VE: different outcomes of interest against which VE is estimated, study designs used to assess VE, sources of bias and confounding, repeat vaccination, waning immunity, population level effects of vaccination, and VE in at-risk populations. Expert Opinion: The estimation of influenza VE has improved with surveillance networks, better understanding of sources of bias and confounding, and the implementation of advanced statistical methods. Future research should focus on better estimates of the indirect effects of vaccination, the biological effects of vaccination, and how vaccines interact with the immune system. Specifically, little is known about how influenza vaccination impacts an individual's infectiousness, how vaccines wane over time, and the impact of repeated vaccination.
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Affiliation(s)
- Kylie E. C. Ainslie
- Research Associate in Influenza Disease Dynamics, MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Michael Haber
- Professor, Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, 1518 Clifton Rd NE, Atlanta, GA 30322, USA
| | - Walt A. Orenstein
- Professor, Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, 1462 Clifton Rd NE, Atlanta, GA 30322, USA
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Oral immunization with a probiotic cholera vaccine induces broad protective immunity against Vibrio cholerae colonization and disease in mice. PLoS Negl Trop Dis 2019; 13:e0007417. [PMID: 31150386 PMCID: PMC6561597 DOI: 10.1371/journal.pntd.0007417] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/12/2019] [Accepted: 04/28/2019] [Indexed: 01/08/2023] Open
Abstract
Oral cholera vaccines (OCVs) are being increasingly employed, but current killed formulations generally require multiple doses and lack efficacy in young children. We recently developed a new live-attenuated OCV candidate (HaitiV) derived from a Vibrio cholerae strain isolated during the 2010 Haiti cholera epidemic. HaitiV exhibited an unexpected probiotic-like activity in infant rabbits, preventing intestinal colonization and disease by wild-type V. cholerae before the onset of adaptive immunity. However, it remained unknown whether HaitiV would behave similarly to other OCVs to stimulate adaptive immunity against V. cholerae. Here, we orally immunized adult germ-free female mice to test HaitiV’s immunogenicity. HaitiV safely and stably colonized vaccinated mice and induced known adaptive immune correlates of cholera protection within 14 days of administration. Pups born to immunized mice were protected against lethal challenges of both homologous and heterologous V. cholerae strains. Cross-fostering experiments revealed that protection was not dependent on vaccine colonization in or transmission to the pups. These findings demonstrate the protective immunogenicity of HaitiV and support its development as a new tool for limiting cholera. Oral cholera vaccines are increasingly used as public health tools for prevention of cholera and curtailing the spread of outbreaks. However, current killed vaccines provide minimal protection in young children, who are especially susceptible to this diarrheal disease, and require ~7–14 days between vaccination and development of protective immunity. We recently created HaitiV, a live-attenuated oral cholera vaccine candidate derived from a clinical isolate from the Haiti cholera outbreak. Unexpectedly, HaitiV protected against cholera-like illness in infant rabbits within 24 hours of administration, before the onset of adaptive immunity. However, HaitiV’s capacity to stimulate adaptive immune responses against the cholera pathogen were not investigated. Here, we report that HaitiV induces immunological correlates of protection against cholera in adult germ-free mice and leads to protection against disease in their offspring. Protection against disease was transferable through the milk of the immunized mice and was not due to transmission or colonization of HaitiV in this model. Coupling the immunogenicity data presented here with our previous observation that HaitiV can protect from cholera prior to the induction of adaptive immunity, we propose that HaitiV may provide both rapid-onset short-term protection from disease while eliciting stable and long-lasting immunity against cholera.
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Effectiveness of oral cholera vaccine in preventing cholera among fishermen in Lake Chilwa, Malawi: A case-control study. Vaccine 2019; 37:3668-3676. [PMID: 31133470 DOI: 10.1016/j.vaccine.2019.05.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 05/04/2019] [Accepted: 05/13/2019] [Indexed: 12/15/2022]
Abstract
BACKGROUND In response to a cholera outbreak among mobile, difficult-to-reach fishermen on Lake Chilwa, Malawi in 2016, a novel vaccine distribution strategy exploited the proven vaccine thermostability. Fishermen, while taking the first vaccine dose under supervision, received the second dose in a sealed bag, and were told to drink it two weeks later. This study assessed short-term vaccine protection of this strategy. METHODS Patients with diarrhoea admitted to health facilities around lake were interviewed and a stool sample collected for PCR testing. Vaccine effectiveness was assessed in a case-control test-negative design by comparing cases (PCR-positive for V. cholerae O1) and controls (patients with diarrhoea but PCR-negative) and with the screening method that compared the proportions of vaccinated among cholera cases versus the general fishermen population. RESULTS Of 145 study participants, 120 were fishermen living on the lake. Vaccine effectiveness at three-months was 90.0% [95%CI:38.8;98.4] among fishermen and 83.3% [95%CI: 20.8; 96.5] among all participants in the case-control test-negative design, and 97.5% [95%CI: 90.9;99.3] with the screening method. CONCLUSION This strategy was effective in providing short-term protection in fishermen against cholera. Further research is needed to determine the adding value of the second dose and to identify the optimal vaccination strategies for different contexts.
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Franke MF, Ternier R, Jerome JG, Matias WR, Harris JB, Ivers LC. Long-term effectiveness of one and two doses of a killed, bivalent, whole-cell oral cholera vaccine in Haiti: an extended case-control study. LANCET GLOBAL HEALTH 2019; 6:e1028-e1035. [PMID: 30103980 PMCID: PMC6190920 DOI: 10.1016/s2214-109x(18)30284-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/22/2018] [Accepted: 05/30/2018] [Indexed: 01/22/2023]
Abstract
Background No study of long-term protection following killed oral cholera vaccination has been done outside of the historically cholera-endemic areas of south Asia, or has examined protection after a single-dose vaccination regimen. To address this, we examined the duration of protection of the standard two-dose regimen and an incomplete regimen of one dose up to 4 years after vaccination in Haiti. Methods In the setting of two-dose vaccination campaigns with a killed, bivalent, whole-cell oral cholera vaccination, we did a case-control study from October, 2012 through November, 2016. Eligible participants were required to be resident in the vaccine catchment area (Artibonite Department or Central Department) where they were recruited at the start of the study; and be eligible for the vaccination campaign (ie, aged ≥12 months, not pregnant, and living in the region at the time of the vaccine campaign). Patients with cholera had a positive stool culture and were recruited from cholera treatment centres. Community controls were matched to people with cholera by age group, time, and neighbourhood. We did adjusted matched regression analyses to calculate vaccine effectiveness and examine heterogeneity in effectiveness over time. The primary outcome was the effectiveness of one and two oral cholera doses as compared with zero doses from 2 months to 48 months after vaccination, measured by self reporting. Findings Among 178 people assigned to the case group and 706 people assigned to the control group, we found no evidence that two-dose effectiveness decreased during follow-up. In adjusted analyses, the average cumulative 4 year effectiveness for two doses was 76% (95% CI 59–86). In contrast, single-dose effectiveness decreased over time in a log-linear fashion, with a predicted vaccine effectiveness of 79% at the end of 12 months (95% CI 43–93), which declined to zero before the end of the second year. Interpretation In a setting of epidemic and newly endemic cholera in Haiti, single-dose vaccination with killed, bivalent, whole-cell oral cholera vaccination provided short-term protection; however, vaccination with two doses was required for long-term protection, which lasted up to 4 years after vaccination. These results add to the evidence in support of the use of killed, bivalent, whole-cell oral cholera vaccination as part of comprehensive cholera control plans. Funding US National Institute of Allergy and Infectious Diseases of the National Institutes of Health and the Bill & Melinda Gates Foundation.
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Affiliation(s)
- Molly F Franke
- Department of Global Health and Social Medicine, Boston, MA, USA.
| | - Ralph Ternier
- Harvard Medical School, Boston, MA, USA; Partners In Health, Port au Prince, Haiti, MA, USA
| | - J Gregory Jerome
- Harvard Medical School, Boston, MA, USA; Partners In Health, Port au Prince, Haiti, MA, USA
| | - Wilfredo R Matias
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Jason B Harris
- Department of Pediatrics, Boston, MA, USA; Division of Pediatric Global Health, Massachusetts General Hospital, Boston, MA, USA
| | - Louise C Ivers
- Department of Global Health and Social Medicine, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Partners In Health, Port au Prince, Haiti, MA, USA; Center for Global Health, Massachusetts General Hospital, Boston, MA, USA
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Lemaitre J, Pasetto D, Perez-Saez J, Sciarra C, Wamala JF, Rinaldo A. Rainfall as a driver of epidemic cholera: Comparative model assessments of the effect of intra-seasonal precipitation events. Acta Trop 2019; 190:235-243. [PMID: 30465744 DOI: 10.1016/j.actatropica.2018.11.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 11/04/2018] [Accepted: 11/14/2018] [Indexed: 01/18/2023]
Abstract
The correlation between cholera epidemics and climatic drivers, in particular seasonal tropical rainfall, has been studied in a variety of contexts owing to its documented relevance. Several mechanistic models of cholera transmission have included rainfall as a driver by focusing on two possible transmission pathways: either by increasing exposure to contaminated water (e.g. due to worsening sanitary conditions during water excess), or water contamination by freshly excreted bacteria (e.g. due to washout of open-air defecation sites or overflows). Our study assesses the explanatory power of these different modeling structures by formal model comparison using deterministic and stochastic models of the type susceptible-infected-recovered-bacteria (SIRB). The incorporation of rainfall effects is generalized using a nonlinear function that can increase or decrease the relative importance of the large precipitation events. Our modelling framework is tested against the daily epidemiological data collected during the 2015 cholera outbreak within the urban context of Juba, South Sudan. This epidemic is characterized by a particular intra-seasonal double peak on the incidence in apparent relation with particularly strong rainfall events. Our results show that rainfall-based models in both their deterministic and stochastic formulations outperform models that do not account for rainfall. In fact, classical SIRB models are not able to reproduce the second epidemiological peak, thus suggesting that it was rainfall-driven. Moreover we found stronger support across model types for rainfall acting on increased exposure rather than on exacerbated water contamination. Although these results are context-specific, they stress the importance of a systematic and comprehensive appraisal of transmission pathways and their environmental forcings when embarking in the modelling of epidemic cholera.
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Affiliation(s)
- Joseph Lemaitre
- Laboratory of Ecohydrology, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Damiano Pasetto
- Laboratory of Ecohydrology, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Javier Perez-Saez
- Laboratory of Ecohydrology, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Carla Sciarra
- Dipartimento di Ingegneria dell'Ambiente, del Territorio e delle Infrastrutture, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
| | | | - Andrea Rinaldo
- Laboratory of Ecohydrology, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Dipartimento ICEA, Università di Padova, 35100 Padova, Italy.
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The cholera outbreak in Yemen: lessons learned and way forward. BMC Public Health 2018; 18:1338. [PMID: 30514336 PMCID: PMC6278080 DOI: 10.1186/s12889-018-6227-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/19/2018] [Indexed: 01/05/2023] Open
Abstract
The Yemen cholera outbreak has been driven by years of conflict and has now become the largest in epidemiologically recorded history with more than 1.2 million cases since the beginning of the outbreak in April, 2017. In this report we review and discuss the cholera management strategies applied by the major international humanitarian health organizations present in Yemen. We find the response by the organizations examined to have been more focused on case management than on outbreak prevention. Oral Cholera Vaccines (OCVs) were not delivered until nearly 16 months into the outbreak. A recent scale-up of the global OCV stockpile will hopefully allow for rapid mass deployment of the OCV in future humanitarian emergencies. Continuous funding to this stockpile will be crucial to maintain this option for prevention and control of cholera outbreaks. Of equal importance will be the timely recognition of the need for mass OCV deployment and development of more specific, comprehensive and actionable evidence-based frameworks to help guide this decision, however difficult this may be. The outbreak highlights the importance for international humanitarian health organizations to have a continuous discussion about whether and to what extent they should increase their focus on pre-emptively addressing the environmental determinants of communicable diseases in humanitarian emergencies. Strong advocacy from the public health community for peace and the protection of human health, by bringing to attention the public health impacts of armed conflict and keeping the world’s political leaders accountable to their actions, will remain crucial.
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