Safety and immunogenicity of a hexavalent DTwP-IPV-HB-PRP∼T vaccine versus separate DTwP-HB-PRP∼T and IPV vaccines in healthy infants in India

Background: type b (Hib), and inactivated poliomyelitis (IPV) antigens allow the provision of a high-quality, affordable DTwP-IPV-HB-PRP∼T vaccine. Methods: Phase I/II, randomized, active-controlled, open-label study in healthy toddlers (Cohort I) and infants (Cohort II). Toddlers in Cohort I who had completed primary series D, T, P, HB, Hib, and polio vaccination received a booster dose of DTwP-IPV-HB-PRP∼T (N = 30) or DTwP-HB-PRP∼T + IPV (N = 15) vaccines at 15-18 months of age. After satisfactory review of safety data in Cohort I, infants in Cohort II received DTwP-IPV-HB-PRP∼T (N = 100) or DTwP-HB-PRP∼T + IPV (N = 50) at 6-8, 10-12, and 14-16 weeks of age. All infants in Cohort II had received previous oral polio and HB vaccines per country recommendations. Results: Booster and primary series vaccinations were well tolerated with no clinically significant differences between vaccine groups. Most adverse events were mild and resolved spontaneously; there were no vaccine-related serious adverse events and no deaths. In both vaccine groups, anti-D, anti-T, anti-HB, anti-Hib, and anti-polio 1, 2, and 3 seroprotection was 100% post-booster and post-primary series. For the pertussis antigens, booster response rate was > 86% in both groups. For the primary series, vaccine response rate was slightly higher for DTwP-IPV-HB-PRP∼T than DTwP-HB-PRP∼T + IPV for anti-PT (80.2% and 70.8%) and anti-FHA (81.3% and 68.8%), slightly lower for anti-PRN (72.5% and 81.3%), and similar in each group for anti-FIM (95.6% and 97.9%). Conclusions: This study demonstrated a good safety and immunogenicity profile of the hexavalent DTwP-IPV-HB-PRP∼T vaccine for infant primary series vaccination at 6-8, 10-12, and 14-16 weeks of age and booster vaccination at 15-18 months of age and supported progression to the next development phase.