Acellular pertussis vaccine at birth lowered toxoid IgG antibodies
Children who received a monovalent acellular pertussis vaccine at birth had lower pertussis toxoid immunoglobulin G antibodies after the booster dose compared with children who received their first dose at age 8 weeks, according to recent study findings published in The Pediatric Infectious Disease Journal.
Nicholas Wood, MBBS, FRACP, PhD, of the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases in Australia, and colleagues evaluated 76 neonates between 2007 and 2010 to determine antibody and cell-mediated immunity to pertussis 4 years after vaccination. Participants were randomly assigned into three groups: acellular pertussis vaccine and hepatitis B vaccine within 4 days of birth and an additional acellular pertussis vaccine at age 4 weeks (group 1); two acellular pertussis and hepatitis B vaccines at birth (group 2); and only hepatitis B at birth (group 3).
At age 2 years or before and after the 4-year diphtheria-tetanus toxoids-acellular pertussis-polio immunization (DTaP-IPV; Infanrix IPV, GSK Biologicals), pertussis toxoid, filamentous hemagglutinin and pertactin antibody levels were similar among all three groups. Group 1 had higher anti-pertussis antibody levels at age 8 months, but levels were similar among all three groups at age 2 years.
All participants had detectable pertussis antibody levels to pertussis toxoid and pertactin at age 8 months compared with 15% to 18% at age 2 years and 9% to 14% right before the DTaP-IPV booster at age 4 years. However, filamentous hemagglutinin IgG levels were stable from age 2 to 4 years.
Groups 1 and 2 had higher T-helper cell type 2 (Th2) levels compared with group 3.
“In this study, pertussis antibody levels waned significantly by 2 to 4 years old, with <20% having detectable antibodies to both [pertussis toxoid] and [pertactin], thought to equate with protection, and this has implication for the timing of the booster dose of DTaP vaccines, particularly in Australia where a booster dose is no longer given in the second year of life,” the researchers wrote. “We found a non-significant trend to lower [pertussis toxoid] IgG antibodies post the 4 year booster compared with receipt of first dose of [acellular pertussis]-containing vaccine at 8 weeks of age. We also found higher levels of [Th2] cytokines at 2 years from [peripheral blood mononuclear cells] in T-helper-cell dependent memory responses to pertussis vaccine antigens at the birth [acellular pertussis] vaccine cohorts.”
Disclosure: The study was funded in part by the Financial Markets Foundation for Children, Australia, the National Health and Medical Research Council of Australia: Career Development Fellowship, and the Women’s and Children’s Hospital Foundation, South Australia.