Single Dose Oral Cholera Vaccine Study in Dhaka, Bangladesh

Bangladesh remains endemic for cholera, which experiences biannual outbreaks with additional epidemics seen during times of floods, cyclones or any natural disaster. It affects all age groups with the majority of fatal cases occurring in children . Therefore, immunization against cholera remains an important public health component in the prevention and control of the disease .The current two-dose regimen of the internationally available oral cholera vaccines (OCV) create a logistical and programmatic challenge for use in national programs or during epidemics ,so it is important to determine if a single dose vaccine will be protective in regions where cholera is endemic. If the vaccine is found to be efficacious following a single dose, this will have profound implications for the use of the vaccine in areas with limited resources particularly in complex emergencies where a multiple dose regimen is difficult to deploy. A single-dose regimen of this vaccine will improve its 'field ability' and allow the vaccine to be used for outbreak control, especially in difficult settings where the risk of cholera is extremely high and provisions for clean water and sanitation are not available. With low OCV production rates, larger populations could be immunized against cholera if a single dose is found to be efficacious. A single-dose schedule could facilitate the inclusion of a global stockpile strategy. The study design is a two-arm individually randomized double-blind placebo-controlled trial. The primary outcome of the study is the proportion of persons receiving 1 dose of vaccine or placebo who are detected with diarrhea with faecal excretion of V. cholera O1 in the study treatment centres from 7 days to 6 months after dosage and whose identity is confirmed through home visit.