%0 Journal Article
%T Efficacy of a Low-Cost, Inactivated Whole-Cell Oral Cholera Vaccine: Results from 3 Years of Follow-Up of a Randomized, Controlled Trial
%A Dipika Sur
%A Suman Kanungo
%A Binod Sah
%A Byomkesh Manna
%A Mohammad Ali
%A Allison M. Paisley
%A Swapan K. Niyogi
%A Jin Kyung Park
%A Banawarilal Sarkar
%A Mahesh K. Puri
%A Deok Ryun Kim
%A Jacqueline L. Deen
%A Jan Holmgren
%A Rodney Carbis
%A Raman Rao
%A Nguyen Thu Van
%A Seung Hyun Han
%A Stephen Attridge
%A Allan Donner
%A Nirmal K. Ganguly
%A Sujit K. Bhattacharya
%A G. Balakrish Nair
%A John D. Clemens
%A Anna Lena Lopez
%J PLOS Neglected Tropical Diseases
%D 2011
%I Public Library of Science (PLoS)
%R 10.1371/journal.pntd.0001289
%X Background Killed oral cholera vaccines (OCVs) have been licensed for use in developing countries, but protection conferred by licensed OCVs beyond two years of follow-up has not been demonstrated in randomized, clinical trials. Methods/Principal Findings We conducted a cluster-randomized, placebo-controlled trial of a two-dose regimen of a low-cost killed whole cell OCV in residents 1 year of age and older living in 3,933 clusters in Kolkata, India. The primary endpoint was culture-proven Vibrio cholerae O1 diarrhea episodes severe enough to require treatment in a health care facility. Of the 66,900 fully dosed individuals (31,932 vaccinees and 34,968 placebo recipients), 38 vaccinees and 128 placebo-recipients developed cholera during three years of follow-up (protective efficacy 66%; one-sided 95%CI lower bound = 53%, p<0.001). Vaccine protection during the third year of follow-up was 65% (one-sided 95%CI lower bound = 44%, p<0.001). Significant protection was evident in the second year of follow-up in children vaccinated at ages 1¨C4 years and in the third year in older age groups. Conclusions/Significance The killed whole-cell OCV conferred significant protection that was evident in the second year of follow-up in young children and was sustained for at least three years in older age groups. Continued follow-up will be important to establish the vaccine's duration of protection. Trial Registration ClinicalTrials.gov NCT00289224.
%U http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0001289