Diphtheria (D), Tetanus (T), Pertussis (Acellular, Component) (Pa), Hepatitis B (Rdna) (Hbv), Poliomyelitis (Inactivated) (Ipv) And Haemophilus Influenzae Type-B (Hib) Conjugate Vaccine(Glaxosmithkline Plc)

A birth acellular pertussis vaccine may be a valuable alternative for immunity against infant pertussis when a pregnancy pertussis vaccine has not been administered. We assessed whether a birth dose may impair immunoglobulin G (IgG) responses to childhood pertussis boosters.

Children from our previous randomized controlled trial who received a monovalent 3-component aP and hepatitis B vaccine at birth (aP group) or hepatitis B only (control group) followed by Infanrix hexa at 2, 4 and 6 months of age were randomized to receive either high or low-dose diphtheria-tetanus acellular pertussis combination vaccine (DTPa—Infanrix/dTpa—Boostrix) at 18 months and 4 years of age. Serum DTPa-specific IgG was measured pre- and postboost at 18 months and 4 years to determine immunogenicity and potential hyporesponsiveness across vaccination schedules.

Children who received a neonatal aP dose had improved pertussis toxin-IgG persistence and enhanced postvaccination pertactin and filamentous hemagglutinin-IgG responses at 18 months. Hyporesponsiveness was not detected across the study period, and all schedules showed good immunogenicity to subsequent boosters. The high-dose DTPa vaccine consistently induced higher antibody titers than the low-dose dTpa vaccine. Either booster dose was able to bridge immunity between 6 months and 4 years.

A birth dose of acellular pertussis vaccine does not impair antibody responses to booster doses of pertussis vaccines and may be an alternative for protection against early infant pertussis when pertussis booster has not been administered during pregnancy.

Since the introduction of Haemophilus Influenzae type b (Hib) conjugate vaccines, invasive Hib disease has strongly declined worldwide, yet continued control of Hib disease remains important. In Europe, currently three different hexavalent combination vaccines containing Hib conjugates are marketed. In this phase IV, single-blind, randomized, controlled, multi-country study (NCT04535037), we aimed to compare, in a 2 + 1 vaccination schedule, the immunogenicity and safety and show non-inferiority, as well as superiority, of DTPa-HBV-IPV/Hib (Ih group) versus DTaP5-HB-IPV-Hib (Va group) in terms of anti-polyribosylribitol phosphate (PRP) antibody geometric mean concentrations (GMCs) and proportion of participants reaching anti-PRP antibody concentrations greater than or equal to a threshold of 5 µg/mL. One month after the booster vaccination, the anti-PRP antibody GMC ratio (Ih group/Va group) was 0.917 (95% CI: 0.710-1.185), meeting the non-inferiority criteria. The difference in percentage of participants (Ih group - Va group) reaching GMCs ≥5 µg/mL was -6.3% (95% CI: -14.1% to 1.5%), not reaching the predefined non-inferiority threshold. Interestingly, a slightly higher post-booster antibody avidity was observed in the Ih group versus the Va group. Both vaccines were well tolerated, and no safety concerns were raised. This study illustrates the different kinetics of the anti-PRP antibody response post-primary and post-booster using the two vaccines containing different Hib conjugates and indicates a potential differential impact of concomitant vaccinations on the anti-PRP responses. The clinical implications of these differences should be further studied.