TY - JOUR
T1 - Use of oral cholera vaccine as a vaccine probe to define the geographical dimensions of person-to-person transmission of cholera
AU - Ali, Mohammad
AU - Kim, Deok Ryun
AU - Kanungo, Suman
AU - Sur, Dipika
AU - Manna, Byomkesh
AU - Digilio, Laura
AU - Dutta, Shanta
AU - Marks, Florian
AU - Bhattacharya, Sujit K.
AU - Clemens, John
N1 - Funding Information:
We are grateful to the people of the study areas and the field staff for whom the project was successfully conducted. This study was funded by the Bill & Melinda Gates Foundation in grants to the icddr,b, the International Vaccine Institute (IVI), and the DOVE project of Johns Hopkins Bloomberg School of Public Health (OPP1148763). The study was also supported by core grants to the icddr,b from the governments of Bangladesh, Canada, Sweden, and the UK and to the IVI from the governments of Sweden and South Korea. The sponsors had no role in the study design, in the collection, analysis, and interpretation of the data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.
Publisher Copyright:
© 2017 The Author(s)
PY - 2018/1
Y1 - 2018/1
N2 - Background Cholera is known to be transmitted from person to person, and inactivated oral cholera vaccines (OCVs) have been shown to confer herd protection via interruption of this transmission. However, the geographic dimensions of chains of person-to-person transmission of cholera are uncertain. The ability of OCVs to confer herd protection was used to define these dimensions in two cholera-endemic settings, one in rural Bangladesh and the other in urban India. Methods Two large randomized, placebo-controlled trials of inactivated OCVs, one in rural Matlab, Bangladesh and the other in urban Kolkata, India, were reanalyzed. Vaccine herd protection was evaluated by relating the risk of cholera in placebo recipients to vaccine coverage of surrounding residents residing within concentric rings. In Matlab, concentric rings in 100-m increments up to 700 m were evaluated; in Kolkata, 50-m increments up to 350 m were evaluated. Results One hundred and eight cholera cases among 24 667 placebo recipients were detected during 1 year of post-vaccination follow-up at Matlab; 128 cholera cases among 34 968 placebo recipients were detected during 3 years of follow-up in Kolkata. Consistent inverse relationships were observed between vaccine coverage of the ring and the risk of cholera in the central placebo recipient for rings with radii up to 500 m in Matlab and up to 150 m in Kolkata. Conclusions These results suggest that the dimensions of chains of person-to-person transmission in endemic settings can be quite large and may differ substantially from setting to setting. Using OCVs as ‘probes’ to define these dimensions can inform geographical targeting strategies for the deployment of these vaccines in endemic settings.
AB - Background Cholera is known to be transmitted from person to person, and inactivated oral cholera vaccines (OCVs) have been shown to confer herd protection via interruption of this transmission. However, the geographic dimensions of chains of person-to-person transmission of cholera are uncertain. The ability of OCVs to confer herd protection was used to define these dimensions in two cholera-endemic settings, one in rural Bangladesh and the other in urban India. Methods Two large randomized, placebo-controlled trials of inactivated OCVs, one in rural Matlab, Bangladesh and the other in urban Kolkata, India, were reanalyzed. Vaccine herd protection was evaluated by relating the risk of cholera in placebo recipients to vaccine coverage of surrounding residents residing within concentric rings. In Matlab, concentric rings in 100-m increments up to 700 m were evaluated; in Kolkata, 50-m increments up to 350 m were evaluated. Results One hundred and eight cholera cases among 24 667 placebo recipients were detected during 1 year of post-vaccination follow-up at Matlab; 128 cholera cases among 34 968 placebo recipients were detected during 3 years of follow-up in Kolkata. Consistent inverse relationships were observed between vaccine coverage of the ring and the risk of cholera in the central placebo recipient for rings with radii up to 500 m in Matlab and up to 150 m in Kolkata. Conclusions These results suggest that the dimensions of chains of person-to-person transmission in endemic settings can be quite large and may differ substantially from setting to setting. Using OCVs as ‘probes’ to define these dimensions can inform geographical targeting strategies for the deployment of these vaccines in endemic settings.
KW - Cholera
KW - GIS
KW - Herd protection
KW - Oral cholera vaccine
KW - Transmission
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U2 - 10.1016/j.ijid.2017.11.020
DO - 10.1016/j.ijid.2017.11.020
M3 - Article
C2 - 29174695
AN - SCOPUS:85037338872
SN - 1201-9712
VL - 66
SP - 90
EP - 95
JO - International Journal of Infectious Diseases
JF - International Journal of Infectious Diseases
ER -