A “birth” dose of pertussis vaccine?

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Pertussis is most deadly in infants too young to have the possibility of protection through vaccination under our current schedule. A variety of strategies have been considered that focus on preventing the young infants' contacts from being a source of B. pertussis – including preconceptual immunization of women of childbearing age, immunization of mother's immediately postpartum, and immunization of all expected contacts of infants, before delivery hospital discharge. Immunization during latter pregnancy also has been considered worthy of evaluation. Each strategy has problems. In this issue of The Journal, Knuf et al present data on an additional possible solution – a “birth” dose of pertussis vaccine. They report the results of a prospective study, entering 121 infants 2-5 days of age who were randomized to receive an investigational three-antigen, stand-alone, acellular pertussis vaccine (aP) or hepatitis B vaccine. The same combination vaccine (DTaP-HBV-IPV/Hib) was given to both groups at 2, 4, and 6 months of age.

Neonates who received aP had bolstered pertussis antibodies at 3 months while the control group generally continued to a nadir of passively acquired maternal antibody. Pertussis antibodies as well as poliovirus, diphtheria, and tetanus antibodies at 7 months of age were similar in both groups. However, the infants who received the birth dose of aP had significantly lower antibodies to Haemophilus influenzae type b. Immunologic responsiveness, tolerance, and blunting are complex vaccine issues, especially at play in the neonate.