Cholera is an important public health problem worldwide, particularly in endemic areas of the developing world. In 2004, 101 383 cholera cases and 2345 deaths were reported to the WHO. Provision of safe water and food, adequate sanitation and improved personal and community hygiene are the main public health interventions against cholera. These measures cannot be implemented in the near future in the most cholera-endemic areas.~Phase II trials of this reformulated killed oral cholera vaccine were performed in SonLa, Vietnam and Kolkata, India. Significant vibriocidal antibody responses were observed among vaccine recipients.~Distribution of 2 doses of the cholera vaccine is often difficult in field settings and limits its utility in emergency situations, since an interval of 2 weeks is usually required between doses. Recent data from Vietnam suggests that greater vibriocidal responses following 2 doses are elicited compared to previous formulations. Furthermore, in a study in Bangladesh comparing immune responses to the vaccine among children supplemented with vitamin A and zinc, seroconversion after the first dose was robust in all groups suggesting that one dose may be used in the control of cholera.~Data regarding the immune response following one dose of this reformulated vaccine is currently unavailable. If a single dose of this vaccine is confirmed to be immunogenic to recipients, then this vaccine may be used more extensively for public health purposes, especially during times of outbreaks.~The objective of this study is to confirm the safety of the killed oral cholera vaccine among adult and children volunteers.
The purpose of this study is to compare the safety and immunogenicity of one and two doses of the killed oral cholera vaccine.