The immunological response of Nigerian infants to attenuated and inactivated poliovaccines.

A comparison was made of the immunity conferred by injected formalin-killed poliomyelitis vaccine and orally administered attenuated poliomyelitis vaccine in Nigerian infants under tropical conditions where interfering enteroviruses have caused poor conversion rates with attenuated poliomyelitis vaccine. Two hundred and thirty infants completed the immunization schedules. The levels of antibodies to polioviruses were assessed before immunization and at periodic intervals during the trial. Seventy-four per cent, 72% and 85% of the children lacked antibodies to poliovirus types 1, 2 and 3 respectively at 6 months if they received no vaccine, the comparative proportions respectively were 52%, 8% and 48% if they had oral attenuated poliovaccine and 2%, 4% and 0% if they had three doses of inactivated poliovaccine. It is suggested that killed poliovaccine incorporated in a quadruple vaccine may have a place in developing countries like Nigeria in the control of diphtheria, tetanus, whooping cough and poliomyelitis.