Oral Iodine Supplementation Does Not Reduce Neutralizing-Antibody Responses to Oral Poliovirus Vaccine 919

In a recent clinical trial, dietary supplementation with a single dose of oral iodized oil (OIO) improved the survival of infants in a population at risk for mild-to-severe iodine deficiency disorders. The study was designed so that OIO was administered at the first visit for the recommended childhood vaccination schedule of the WHO Expanded Programme on Immunization (EPI). Placebo or OIO was administered immediately following trivalent oral poliovirus vaccine (OPV). An important concern was that OIO might have a deleterious effect on OPV, since polioviruses are inactivated by iodine, or might otherwise reduce immune responses to the vaccine. Serum samples were collected upon enrollment of infants at 6-10 weeks of age and again at the final follow-up evaluation at 6 months of age. Pre-immune and post-immune sera from 478 infants were tested for virus-neutralizing antibody activity against each of the three poliovirus serotypes. Iodine supplementation did not reduce immune responses to OPV. These results indicate that supplementation with OIO may be combined with delivery of the first dose of OPV in the EPI schedule.