Immunogenicity of enhanced potency inactivated polio vaccine

Fifty two children were immunized with two doses of enhanced potency inactivated polio vaccine in order to determine its efficacy. The vaccine was very efficacious with 92.3, 92.3 and 88.3% of the children seroconverting to the three poliovirus types, respectively. The vaccine was equally efficacious whether the two doses were given at 4-week or 8-week intervals or when immunization was started at 6-7 weeks of age or later. The presence of maternal antibodies did not interfere significantly with the seroresponse to two doses of IPV-E. The study recommends that two doses of IPV-E give satisfactory seroconversion rates. Immunization can be started as early as 6 weeks age and the two doses can be given at 4 weeks interval to complete primary immunization against poliomyelitis.