TY - JOUR
T1 - 5 year efficacy of a bivalent killed whole-cell oral cholera vaccine in Kolkata, India
T2 - A cluster-randomised, double-blind, placebo-controlled trial
AU - Bhattacharya, Sujit K.
AU - Sur, Dipika
AU - Ali, Mohammad
AU - Kanungo, Suman
AU - You, Young Ae
AU - Manna, Byomkesh
AU - Sah, Binod
AU - Niyogi, Swapan K.
AU - Park, Jin Kyung
AU - Sarkar, Banwarilal
AU - Puri, Mahesh K.
AU - Kim, Deok Ryun
AU - Deen, Jacqueline L.
AU - Holmgren, Jan
AU - Carbis, Rodney
AU - Dhingra, Mandeep Singh
AU - Donner, Allan
AU - Nair, G. Balakrish
AU - Lopez, Anna Lena
AU - Wierzba, Thomas F.
AU - Clemens, John D.
PY - 2013/12
Y1 - 2013/12
N2 - 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.
AB - 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.
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U2 - 10.1016/S1473-3099(13)70273-1
DO - 10.1016/S1473-3099(13)70273-1
M3 - Article
C2 - 24140390
AN - SCOPUS:84887624420
SN - 1473-3099
VL - 13
SP - 1050
EP - 1056
JO - The Lancet Infectious Diseases
JF - The Lancet Infectious Diseases
IS - 12
ER -