Seroconversion following killed polio vaccine in neonates.

ABSTRACT

The study was carried out to evaluate the efficacy of IPV in neonates and to study the additive effect of IPV or OPV at birth on seroconversion with three subsequent doses of OPV. Addition of IPV or OPV at birth to the conventional OPV schedule resulted in significantly higher seroconversion rates than in the controls, who received three doses of OPV. Three doses of IPV beginning from birth resulted in significantly better seroconversion rates than in the control group. Children receiving 3 doses of IPV showed significantly greater seroconversion rates against type III polio virus than those receiving IPV/OPV at birth followed by 3 doses of OPV. The difference in the seroconversion rates against the other virus types was not significant. A significantly greater number of children who received some vaccine at birth (IPV or OPV) were protected against poliomyelitis by 6 weeks age as compared to those who received no immunization at birth. The study recommends that seroconversion rates following three doses of IPV are satisfactory. Addition of IPV or OPV at birth to the conventional schedule markedly increases the seroconversion rates. Immunization can be started at birth to ensure early protection against poliomyelitis.