Poliovirus vaccines in mineral oil adjuvant: II. Clinical reaction and antibody response

Purified aqueous poliovirus vaccine containing a total of 4.6γ of viral substance per dose was highly effective in immunizing very young infants against poliovirus. Eighty-three, 55, and 84 per cent of infants responded serologically with neutralizing antibody when given three doses of vaccine in the primary series. Essentially all responded with high titer when the booster dose of vaccine was given 7 months later. Emulsified mineral oil adjuvant vaccine, containing only 0.46γ of viral antigen per dose and given in only two doses, effected seroconversion of 52 per cent, 42 per cent, and 48 per cent of infants to poliovirus types I, II, and III, following the primary immunization series and 90 per cent, 80 per cent, and 87 per cent, respectively, were converted to the three types following the booster dose. Even better results would likely have been obtained had three doses been given initially. A generally poorer antibody response was obtained with the use of Salk vaccine than with the aqueous and adjuvant purified vaccines. None of the infants developed significant local or systemic reaction to the vaccine. Roughly, 30 children were included in each of the three vaccine groups in the study.