A Randomized Study of the Safety and Immunogenicity of DTPa-HB-IPV Vaccine Administered as Three Doses or in a Sequential IPV/OPV Schedule at 2, 4, and 6 Months of Age ♦ 933

Introduction: In 1997 the ACIP and the AAP expanded polio vaccine recommendations to include schedules for all IPV and sequential IPV/OPV use. As a result, the number of vaccine injections needed per visit increased (up to 4). In this study we evaluated two combination formulations: DTPa-HB-IPV and DTPa-HB (SB Bio.). Methods: 400 infants were immunized at 2, 4, and 6 months in a randomized, serologically blinded evaluation of the safety and immunogenicity of four vaccine regimens: Group A--all DTPa-HB-IPV; Group B--DTPa-HB-IPVat 2 and 4 mo and DTPa-HB and OPVat 6 mo; Group C--all DTPa-HB and IPV; Group D--DTPa and HB and OPV. Hib vaccine was given separately to all. Results: There were no vaccine-related serious adverse events. Ascertained adverse events (fever, irritability, local reactions) were similar between groups. Polio virus type 1, 2, and 3 immune responses at 7 mo are shown below. Immune responses to Hib, Hep B, diphtheria, tetanus and pertussis(3 antigens) were similar between groups. Table

Table 1 No caption available.

Conclusions: DTPa-HB-IPV had comparable safety and immunogenicity for Polio type 1, 2, 3 and all other antigens compared with IPOL(IPV) given separately. DTPa-HB-IPV in sequential use with OPV or OPV alone induced higher GMT for Polio type 1 and significantly higher GMT for type 2, but had similar seropositive rates. Combination DTPa-HB and DTPa-HB-IPV vaccines appear to be safe and immunogenic and will reduce the number of injections needed for immunizations.