Effectiveness of a Bivalent Killed Whole Cell Based Oral Cholera Vaccine

Inclusion criteria for cases of the main case-control study are as follows: * Giving verbal informed consent/assent, or in the case of minors, a parent or guardian give informed consent to participate in the study * Living in the study area since the start of the mass vaccination * Submitted a faecal specimen * Whose residence could be located * Whose stool specimens yield V. cholera O1 or O139 * Belonging to study population through census database Exclusion criteria: * Not giving verbal informed consent/assent, or in the case of minors, a parent or guardian does not give informed consent to participate in the study * Not living in the study area since the start of the mass vaccination * No faecal specimen * Whose residence could not be located * Whose stool specimens does not yield V. cholera O1 or O139 * Not belonging to study population through census database