Pertussis vaccination during pregnancy reduces the risk of infection in infants by 65%, with no evidence that the ‘blunting’ effects of maternal antibodies compromise infant immunity, Australian doctors say.

Vaccine effectiveness data from 280,000 mother–infant pairs also show that maternal diphtheria, tetanus and acellular pertussis (DTaP) vaccination protects against disease for eight months, which is two months longer than previously reported.

The Curtin University–led team said, while their results confirmed the reduced effectiveness of the third dose in maternally vaccinated infants, this did not translate to greater risk of disease.

“Maternal antibodies may ‘blunt’ the response of infants to primary immunisation, but maternal and/or infant antibodies are sufficient to protect maternally vaccinated infants from infection,” they wrote.