MA SANTE, Cameroon
WHO’s cholera roadmap assumes that an oral cholera vaccine (OCV) campaign should be repeated after three years. This assumption is based on efficacy data following initial doses but there is no evidence of responses following revaccination. People who were fully vaccinated earlier may respond with a booster response to a later dose and a single dose will be sufficient.
We plan to recruit subjects who were vaccinated in Mogode, Cameroon in 2017 and give them a single dose of OCV and then monitor their immune response. We will stratify the subjects into those who took zero, one or two doses of OCV during the earlier campaign. We will also stratify by age group to determine if there is an age-specific response. A booster response should be evident by the early serum response (4 or 5 days) following the booster dose rather than the usual response at 7–10 days.