5 year efficacy of a bivalent killed whole-cell oral cholera vaccine in Kolkata, India: A cluster-randomised, double-blind, placebo-controlled trial

Sujit K. Bhattacharya, Dipika Sur, Mohammad Ali, Suman Kanungo, Young Ae You, Byomkesh Manna, Binod Sah, Swapan K. Niyogi, Jin Kyung Park, Banwarilal Sarkar, Mahesh K. Puri, Deok Ryun Kim, Jacqueline L. Deen, Jan Holmgren, Rodney Carbis, Mandeep Singh Dhingra, Allan Donner, G. Balakrish Nair, Anna Lena Lopez, Thomas F. WierzbaJohn D. Clemens

Research output: Contribution to journalArticle

Abstract

Background: Efficacy and safety of a two-dose regimen of bivalent killed whole-cell oral cholera vaccine (Shantha Biotechnics, Hyderabad, India) to 3 years is established, but long-term efficacy is not. We aimed to assess protective efficacy up to 5 years in a slum area of Kolkata, India. Methods: In our double-blind, cluster-randomised, placebo-controlled trial, we assessed incidence of cholera in non-pregnant individuals older than 1 year residing in 3933 dwellings (clusters) in Kolkata, India. We randomly allocated participants, by dwelling, to receive two oral doses of modified killed bivalent whole-cell cholera vaccine or heat-killed Escherichia coli K12 placebo, 14 days apart. Randomisation was done by use of a computer-generated sequence in blocks of four. The primary endpoint was prevention of episodes of culture-confirmed Vibrio cholerae O1 diarrhoea severe enough for patients to seek treatment in a health-care facility. We identified culture-confirmed cholera cases among participants seeking treatment for diarrhoea at a study clinic or government hospital between 14 days and 1825 days after receipt of the second dose. We assessed vaccine protection in a per-protocol population of participants who had completely ingested two doses of assigned study treatment. Findings: 69 of 31932 recipients of vaccine and 219 of 34968 recipients of placebo developed cholera during 5 year follow-up (incidence 2·2 per 1000 in the vaccine group and 6·3 per 1000 in the placebo group). Cumulative protective efficacy of the vaccine at 5 years was 65% (95% CI 52-74; p<0·0001), and point estimates by year of follow-up suggested no evidence of decline in protective efficacy. Interpretation: Sustained protection for 5 years at the level we reported has not been noted previously with other oral cholera vaccines. Established long-term efficacy of this vaccine could assist policy makers formulate rational vaccination strategies to reduce overall cholera burden in endemic settings. Funding: Bill & Melinda Gates Foundation and the governments of South Korea and Sweden.

Original languageEnglish (US)
Pages (from-to)1050-1056
Number of pages7
JournalThe Lancet Infectious Diseases
Volume13
Issue number12
DOIs
StatePublished - Dec 1 2013

ASJC Scopus subject areas

  • Infectious Diseases

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    Bhattacharya, S. K., Sur, D., Ali, M., Kanungo, S., You, Y. A., Manna, B., Sah, B., Niyogi, S. K., Park, J. K., Sarkar, B., Puri, M. K., Kim, D. R., Deen, J. L., Holmgren, J., Carbis, R., Dhingra, M. S., Donner, A., Nair, G. B., Lopez, A. L., ... Clemens, J. D. (2013). 5 year efficacy of a bivalent killed whole-cell oral cholera vaccine in Kolkata, India: A cluster-randomised, double-blind, placebo-controlled trial. The Lancet Infectious Diseases, 13(12), 1050-1056. https://doi.org/10.1016/S1473-3099(13)70273-1