Effect of vitamin A administration on response to oral polio vaccination

To evaluate the effect of simultaneous administration of vitamin A and Oral Polio Vaccine (OPV) on seroconversion to OPV a randomized double-blind, placebo-controlled trial was conducted. Fifty-seven infants were randomly given either 50,000 I.U. vitamin A (n=34) or placebo (n=23) with each OPV vaccine at monthly intervals. Seroconversion to polio were 81% (79% in vitamin A group and 83% in placebo group, p=0.76) for polio virus type 1, 86% (82% in vitamin A group and 91% in placebo group, p=0.34) for polio virus type 2, and 84% (82% in vitamin A group and 87% in placebo group, p=0.64) for polio virus type 3. A multiple logistic regression model was done to examine the factors associated with reduced seroconversion (polio virus type 1). For adequate vitamin A status the adjusted odds ratio of seroconversion was 0.24 (95% CI: 0.04-1.49, p=0.11) and that for high maternal antibody was 0.11 (95% CI: 0.02-0.68, p=0.015). The geometric mean titer (GMT) was significantly lower in infants with adequate vitamin A stores compared to vitamin A deficient infants (p=0.04; Mann-Whitney test). The results of this study suggest that vitamin A supplementation had no effect on seroconversion, however, in children with adequate vitamin A status there was a trend towards lower seroconversion. High maternal antibody was significantly associated with reduced seroconversion to the oral polio vaccine.