Impact Evaluation of Oral Cholera Vaccination in a Rural Setting Using the National Immunization System of Bangladesh

This study in two selected rural cholera endemic unions in Keraniganj Upazila near Dhaka city will continue for two and half years. The study has two major components- 1. Feasibility of intervention with oral cholera vaccine in one union; and, 2. Impact evaluation of the intervention through prospective passive surveillance for diarrheal patients coming from the two selected unions at the upazila health complex. For the cholera vaccination all male and non-pregnant female residents above one year age will be targeted for vaccination in the selected union. Investigators are excluding less than one year children and pregnant woman form vaccination. For the surveillance part a standardized questionnaire will be administered to all consented diarrheal patients or their guardians in order to obtain information on diarrhea, health and demographic issues. Stool samples will be co llected and tested for V. cholerae O1 and O139.

Investigators, purposively, have selected Keraniganj Upazila of Dhaka as the study area due to high incidence of diarrhea and evidence of culture confirmed cholera and its close proximity to Dhaka. Based on the Keraniganj diarrheal disease report and evidence of cholera prevalence in icddr,b surveillance data, the Ruhitpur union with approximately thirty thousand population will be selected as our area for vaccination, the intervention union.

To evaluate the effectiveness of intervention Investigators will include Basta union of Keraniganj as the non-intervention area. In selecting the two unions, to make them comparable, in addition to population size, evidence of diarrhea and cholera, Investigators have considered the closeness to the Upazila Health Complexes (UHC), presence of educational institutes and health facilities, literacy rates, land area, etc.

Investigators will use the killed whole cell oral cholera vaccine, "Shanchol", manufactured by Shantha Biotechnics for the study. The vaccine is registered in India and is prequalified by WHO. In urban Mirpur area investigators have already successfully used more than 265,000 doses of the same vaccine. Vaccines are stored in the EPI(Expanded program on immunization) cold room at 2-8 degree C. Based on available space in District and upazila cold stores, vaccines will be shifted from the EPI cold room facilities in Dhaka. Investigators will use the rural health facilities including community clinics as the vaccination site for vaccinating the catchment eligible targeted population. Investigators will use the existing EPI cold chain facilities at the Keraniganj Upazila health complex to deliver the vaccine in the selected union. During vaccination, vaccinators will gently shake the single dose vial well to disperse the suspension and then open it to feed its content to the recipient. Adults and older children can take the vaccine by themselves but vaccinators will feed the vaccine contents to younger children. Trained Community health care provider, Health Assistants and Family Welfare assistants of the community clinic area will act as vaccinators. There will be adequate training for all concerned prior to the vaccination programme.

In addition, volunteers from the community will be recruited and trained to assist with the vaccination and social mobilization activities. Investigators will develop appropriate communication materials to inform the population about the cholera vaccination opportunity. Local health facilities, pharmacies and community residents will be involved to assist social mobilization of the population to attend vaccination sessions. Persons below one year of age and pregnant women will not receive the vaccine. People living in the adjacent unions will not be eligible to receive the vaccine, due to limited number of vaccines in hand. Investigators will have to clarify in a convincing way through the field workers, community volunteers/leaders and to the stakeholders that everyone cannot be given the intervention because of the targeted approach and unavailability of vaccine for all and because this study is only a feasibility study to test the vaccine delivery mechanism in a rural setting.