Field Application of Shanchol in Adults in Bangladesh

Background: Cholera is a public health problem globally and in Bangladesh and its prevention is important. Despite recent availability of an effective and affordable oral cholera vaccine (OCV), its field application remains a challenge and needs to be addressed in carefully conducted research studies.There is lack of information on temperature sensitivity and resulting immunogenicity of Shanchol OCV and it is not known if administration of two doses of OCVs, one month apart, instead of currently recommended 14 days, to improve success of vaccination programme will be effective;also if one dose of the vaccine, instead of currently recommended two doses, would result in adequate immune response in population exposed to V. cholerae in an endemic country like Bangladesh. Objectives: To determine immunogenicity of Shanchol in adults. when:

1. 1.the vaccine is stored at three defined temperatures(25 oC ,37 oC and 42oC) for 14 days, before putting back in cold box for administration in the field and compare them with the response when the vaccine is stored under currently recommended temperatures.
2. 2.two doses of the vaccine administered one month apart and compared vaccines administered at currently recommended interval of 14 days.
3. 3.a single dose is administered and compare them with responses after recommended two doses.
4. 4.Objective 1: safety and immunogenicity of vaccine in adults after its storage at three defined temperatures (25oC ,37oC and 42oC) by measuring vibriocidal antibody responses and compare them with the findings when the vaccine is stored at currently recommended temperature of 2-8oC (recommended by manufacturer, Shantha Biotechnic).
5. 5.Objective 2: compare vibriocidal responses following administration of two doses of the vaccine one month apart and compare them with vaccination 14 days apart over a period of one year, with study of the memory responses over a one year period as a secondary outcome.
6. 6.Objective 3: compare acute immune responses (vibriocidal antibody) following one and two doses of vaccine, and compare memory response as a secondary outcome measure, over a one year period.