Acellular Pertussis Vaccine Given in the Week After Birth Does Not Impair Antibody Responses to Later Childhood Doses.

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.