Supplementation with Zinc, but Not Vitamin A, Improves Seroconversion to Vibriocidal Antibody in Children Given an Oral Cholera Vaccine

To investigate whether micronutrient supplementation could improve the vibriocidal antibody response of children to a killed oral cholera vaccine, 2–5-year-old children were randomly assigned to receive vitamin A and zinc (AZ group), vitamin A and a placebo (A group), zinc and a placebo (Z group), or both placebos (P group). All children received 2 doses of the vaccine. The number of children who had a ⩾4-fold increase in vibriocidal antibody was significantly greater in the AZ group than in the P group (P=.025–.028). Factorial analysis suggested that the proportion of children with a ⩾4-fold increase in vibriocidal antibody titer was significantly greater in the zinc-supplemented groups than in the groups that did not receive zinc (P=.013–.048) and that vitamin A supplementation did not have a significant effect. Thus, supplementation with zinc improves seroconversion to vibriocidal antibody and, hence, has the potential to improve the efficacy of oral cholera vaccine in children