Background: To evaluate immunogenicity, reactogenicity, and safety of a hexavalent combination vaccine diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus-Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) when coadministered with a 7-valent pneumococcal conjugate vaccine (PCV7).
Methods: Infants received either a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus-H. influenzae type b vaccine concomitantly with PCV7 or DTPa-HBV-IPV/Hib alone infants were vaccinated at 2, 3 and 4 months (primary immunization) and 12-15 months of age (booster dose). Local and systemic reactions and adverse events were monitored following each dose and compared between groups. Blood was obtained prior to dose 1, one month after dose 3, immediately prior to and 1 month following the booster dose to measure antibody responses to each of the antigens.
Results: Two hundred and fifty-three subjects (PCV7, 127; Control, 126) were enrolled. Antibody responses were compared in 226 subjects for the primary immunization and 212 for the booster dose (per-protocol (PP) population). Although there were some differences in geometric mean concentrations (GMCs) to the DTPa-HBV-IPV/Hib antigens after the primary series, GMCs for all antigens after the booster dose were similar in both groups, except for diphtheria which was significantly higher in the PCV7 group (PCV7, 7.41 IU/mL; Control, 5.78 IU/mL). Reactogenicity and safety data were compared in 252 infants receiving primary immunization and 235 children receiving the booster dose. Site reactions were similar in both groups. Fever >or=38.0 degrees C following each vaccination was reported more frequently in the PCV7 group (28.3-50.0%) than in the Control group (15.6-33.6%) whereas fever >39.0 degrees C occurred only in a few cases and to the same extent in both groups (PCV7, 0.8-2.7%; Control, 1.6-4.1%). Only one reported serious adverse event was characterized as being related to the study vaccines: control subject was hospitalized with a fever.
Conclusion: DTPa-HBV-IPV/Hib and PCV7 were highly immunogenic, well-tolerated and safe when coadministered at 2, 3 and 4 months of age with a booster dose at 12-15 months of age. These results support the coadministration of PVC7 with DTPa-HBV-IPV/Hib as part of the routine immunization schedule for infants and children.