Immune Response to a Delayed Second Dose of Oral Cholera Vaccine

Inclusion Criteria: * Any healthy individual ≥ 1 year-old and younger than 40 years old , eligible for OCV vaccination (not suffering from a medical condition that contraindicates vaccination, i.e. any acute illness, including acute gastrointestinal illness or acute febrile illness). * Living in the study area with no plan to move away over the study period (up to 18 months). * Who provided written informed consent or whose representative (mother, father or main caretaker) provided written informed consent in case of individuals younger than 18 years. A written assent will also be obtained from adolescents (10-17 years) * An individual who (or whose mother, father or main caretaker) is, based on the judgment of the investigator, capable of complying with the study requirements. Exclusion Criteria: * Known history of hypersensitivity reactions to other vaccines. * Individual acutely ill or with signs of infection at the time of enrolment (e.g. fever \> 38⁰C) * Gastrointestinal symptoms including nausea, vomiting, diarrhea, or decreased appetite within 24 hours prior to study initiation . * Diarrhea, administration of antidiarrheal drugs or antibiotics to treat diarrhea or abdominal pain either lasting 2 weeks or longer within 6 months prior to study initiation, or occurring during the week before study initiation. * Other vaccination within 1 week prior to study initiation or planned vaccination during the following month after vaccine intake . * Participation in another tr…