Skip to Main content Skip to Navigation
New interface
Journal articles

Letter to the Editor Questioning the Effectiveness of Oral Cholera Vaccine in Port-au-Prince Slums

Abstract : Oral cholera vaccination (OCV) has been validated by the World Health Organization (WHO) as a valuable tool to complement water, sanitation, and hygiene (WASH) activities in cholera prevention for high-risk areas and populations. We read with great interest the recent study published by Sévère and others, which evaluated the effectiveness of a mass OCV campaign targeting approximately 70,000 inhabitants in several slums of Port-au-Prince, Haiti, between April and June 2012. The authors reported a 75% vaccine coverage and, using a cohort design, a striking 97.5% vaccine effectiveness in the 37 months postvaccination, whereas controlled clinical trials have measured OCV vaccine efficacy around 57% [95% confidence interval, 44–67%] during the first 2 years. Although it was expected that 56% of cholera cases would occur among vaccinated individuals according to the WHO screening method, the same proportion was 5% in the Sévère and others cohort. A thorough analysis of this study shows that the authors did not evaluate the isolated effectiveness of OCV. They rather estimated its combined effectiveness together with WASH-associated measures. To assess the importance of such methodological bias, we computed provided data using a bias-indicator cohort analysis, as previously described in another OCV campaign, and found that their strategy exhibited a 95% effectiveness [93–97%] against noncholeric diarrheas as well. Pondering such bias would require adjusting the results on the observance of WASH prevention methods, which may have differed between nonvaccinated and vaccinated groups.
Complete list of metadata

Cited literature [7 references]  Display  Hide  Download
Contributor : Jean Gaudart Connect in order to contact the contributor
Submitted on : Monday, September 19, 2016 - 5:33:44 PM
Last modification on : Thursday, June 9, 2022 - 12:10:02 PM


Publication funded by an institution


Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives 4.0 International License




Stanilas Rebaudet, Jean Gaudart, Aaron Aruna Abedi, Renaud Piarroux. Letter to the Editor Questioning the Effectiveness of Oral Cholera Vaccine in Port-au-Prince Slums. American Journal of Tropical Medicine and Hygiene, 2016, 95 (2), pp.4932-494. ⟨10.4269/ajtmh.16-0314a⟩. ⟨hal-01368624⟩



Record views


Files downloads