Role of maternal pertussis antibodies in infants.

Pertussis remains a serious infection in young infants. Most deaths occur in the first 3 months of life, before administration of the first dose of pertussis vaccine. Pertussis antibodies are transferred from mother to infant; but because of the lack of serologic correlates of protection, it is difficult to determine the proportion of infants born with a protective concentration of maternal antibodies. Indirect evidence suggests that maternal antibodies provide short lived protection against fatal pertussis. It is hoped that the protection of young infants could be enhanced by maternal or neonatal vaccination. The possibility of protecting young infants against pertussis by immunizing their mothers during pregnancy was investigated in the 1930s and 1940s; no further studies have been published since. Recent animal and human studies have provided evidence that neonatal immunization with acellular pertussis vaccine can efficiently prime T and B cells and act as a basis for future immune response. The limited data on neonatal and maternal pertussis immunization are promising and call for further research to reduce the vulnerability of young infants to pertussis disease.