Introduction of Cholera Vaccine in Bangladesh (ICVB)

Introduction of Cholera Vaccine in Bangladesh: " Impact Evaluation of Cholera Vaccine and Behaviour Change Interventions in Urban Dhaka"

Bill and Melinda Gates Foundation, Directorate General of Health Services, Ministry of Health and Family Welfare, Bangladesh, International Vaccine Institute, Dhaka City Corporation, Ministry of Local Government and Rural Development, Bangladesh, School of Public Health and Health Professions, University at Buffalo, USA, Johns Hopkins Bloomberg School of Public Health, University of Maryland

The purpose of this study is to conduct and evaluate the feasibility and effectiveness of a mass cholera vaccination program to reduce diarrhea due to Vibrio cholerae in a high incidence urban area. This study will also evaluate the feasibility of adding a household hand washing and safe drinking water promotion intervention to a cholera vaccine program and the overall impact of this combination on decreasing the incidence of diarrhea due to Vibrio cholerae.

Cholera continues to be a major cause of morbidity and mortality in low income countries including Bangladesh. It is estimated that there are at least 300,000 severe cases and 1.2 million infections in people in Bangladesh each year. Deaths annually from cholera may have decreased but overall morbidity remains high. The project for "Introduction of Cholera Vaccine in Bangladesh" (ICVB) will examine the effectiveness of intervention with an oral cholera vaccine in reducing incidence of cholera in urban Dhaka, and the effectiveness of a handwashing and home water treatment behaviour change intervention in reducing diarrhea due to cholera. The proposal involves evaluation of a 2-dose regimen of an oral killed whole cell (WC) vaccine and a handwashing and home water treatment behavior change program promoting improved hygiene and home drinking water treatment in reducing dehydrating diarrhea in a low income area of Dhaka, Bangladesh. The study population will include 90 clusters (neighborhoods) in an area of high cholera incidence in Mirpur with a total study population of 240,000. Thirty clusters (approximately 80,000 people) will receive cholera vaccine alone, 30 clusters will receive both cholera vaccine and behavior change and 30 neighborhoods will continue their standard habits and practices. Surveillance for cholera and diarrhea will be carried out in all the three areas during the whole project period. Following the GIS mapping and census of the target populations, the cholera vaccine will be offered to all males and non-pregnant females aged one year and above in the vaccination areas, and an aggressive hygiene and safe water promotion program will be implemented in the 30 behavior change communication clusters. Passive surveillance for cholera will be undertaken using the two ICDDR,B diarrhea treatment facilities as well as 10 other health facilities that serve the study areas. Vaccine and other public health coverage and costs effectiveness as well cost-benefit will be measured, followed by surveillance and identical follow-up studies. The hygiene and safe water behavior change program will also be continued for 4 years. The impact of interventions will be assessed by following vaccination by directly comparing the incidence of cholera and diarrhea in the intervention communities to the incidence in the standard habits and practices communities.

Cholera vaccine, Behaviour change intervention, Cost effectiveness and cost-benefit, Prevention of cholera, Control of Cholera, Vaccination

Each dose of the vaccine contains whole cell Killed inactivated V.cholerae O1 and O139 strains.Vaccine is packaged as liquid formulations in 1.5-ml doses. The vaccine is given two doses separated by a two week interval and administered orally.

Together with vaccination the community health worker will offer a hand washing station and water treatment facilities that include both hardware and a software component. The idea of the handwashing station is to bring together with soap and water that people need for handwashing, especially for handwashing after defecation. The hardware for water treatment is a chlorine dispenser that is a reservoir which holds sodium hypochlorite and dispenses a measured dose of the dilute sodium hypochlorite into a 15 liter water tank. Community residents can collect water directly from the 15 L water tanks into their own personal water storage vessels. The community health worker will negotiate with compound residents for the development of a water treatment system.

The primary analyses will be comparison of the incidence of primary outcome in the intervention clusters compared to the non-intervention cluster

Vaccine-induced protective immunity will be estimated from comparing the incidence of cholera among vaccine recipients in the vaccination area and the incidence of cholera among vaccine non-recipients in the same area.

Indirect protection (herd protection), the protection of non-vaccinated persons due to reduced transmission of an infection, will be estimated from comparing the incidence of cholera among non-vaccinees in the vaccination area and the incidence of cholera in the control area.

Assessment of the impact of the combined cholera vaccine and behavior change intervention on the incidence of all diarrheas treated at the ICDDRB and other health facilities.

Inclusion Criteria: Apparently healthy residents of selected vaccination sites Aged 1 year and above Non-pregnant women Written informed consent Exclusion Criteria: Age less than 1 year Pregnant women

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