Claudio Lanata, Betzana Zambrano, Lucie Ecker, Isabel Amemiya, Ana Gil and Eduardo Santos Lima
Objectives: To assess the immunogenicity and safety of a new candidate, fully liquid, hexavalent DTaP-IPVHep B-PRP-T vaccine (Hexaxim™, an AcXim family vaccine) compared to a licensed hexavalent DTaP-IPV-Hep B// PRP-T vaccine (Infanrix hexa®) in Peru. Methods: Infants born to HBsAg seronegative mothers and who had not received a hepatitis B vaccine prior to entry into the study were randomized to receive either Hexaxim™ (Group 1) or Infanrix hexa® (Group 2) at 2, 4, 6 months of age. Seroprotection (SP) rate for hepatitis B (anti-Hep B antibody concentration ≥10 mIU/mL) was analysed for non-inferiority (Group 1 minus Group 2) 1 month post-primary series. Anti-diphtheria and anti-polyribosyribitol phosphate (PRP) antibody responses were analysed descriptively. Safety was analysed from parental reports. Results: Seroprotection rate for anti-Hep B antibody titers ≥10 mIU/mL was high in both groups (≥99.2%) and non-inferiority was demonstrated (lower bound of the 95% CI for the difference was -4.17, above the pre-defined delta [-10%]). Post-primary SP rates for anti-diphtheria (≥95.5% ≥0.01 IU/mL), anti-PRP (≥99.2% ≥0.15 μg/mL), and anti-Hep B ≥100 mIU/mL (≥93.9%), were similar in each group. Both vaccines were well tolerated. The incidence of serious adverse avents was low and similar in each group, and none was considered to be vaccine related. Conclusions: In a 2, 4, 6 month schedule in Peruvian infants, the investigational DTaP-IPV-Hep B-PRP-T fully liquid vaccine provided high immunogenicity for Hep B, diphtheria and PRP vaccine antigens that was comparable to the licensed hexavalent vaccine. Both vaccines had a similar safety profile.