The immunogenicity of oral poliomyelitis vaccine in a primary vaccination series at 2, 4 and 6 months given concurrently with Hib, hepatitis B and diphtheria, tetanus and whole-cell pertussis vaccines administered as three separate injections or as a combination pentavalent vaccine.

The increasing number of infant immunisations has spurred development of novel combination vaccines. This investigation assesses the immunogenicity of oral poliomyelitis vaccine (OPV) under current and possible new conditions, to help ensure vaccination regimes continue to provide optimal protection against polio in the final stages of polio eradication. Neutralising antibody titres were measured in approximately 200 infants immunised with OPV at 2, 4 and 6 months in tandem with either a combined pentavalent liquid Haemophilus influenza B (Hib), hepatitis B, diphtheria, tetanus and whole-cell pertussis vaccine or three separate but concurrently administered licensed vaccines (diphtheria, tetanus and whole-cell pertussis (DTP), lyophilised Hib, and hepatitis B). Following three doses of OPV, at least 98% of infants demonstrated neutralising antibodies at 1:8 to each poliovirus type under both vaccination regimes, and geometric mean titres (GMTs) well above the suggested protective titre were also observed for all poliovirus types. OPV appears to be effective not only in producing protective antibody titres in an extremely high proportion of infants when given in combination with currently licensed vaccines, but also when administered together with the combination pentavalent vaccine under study. This is encouraging for the continued role of OPV in infant immunisation.