Data from a case-control study confirmed that a pertussis vaccine given during pregnancy protected infants from infection after birth.
“Our results provide good evidence for pregnant women and health professionals to make informed decisions about the effectiveness of maternal vaccination in protecting babies from birth,” researchers from Public Health England wrote in Clinical Infectious Diseases. “Health professionals’ advice has been shown to be important in a woman’s intention for influenza vaccination during pregnancy and against pertussis postpartum.”
The researchers studied infants born in England and Wales from Oct. 22, 2012, to July 11, 2013. Cases included 58 infants aged younger than 8 weeks at the onset of disease and had a PCR-confirmed diagnosis of Bordetella pertussis. There were 55 controls without pertussis. The researchers obtained information about the mothers’ immunization status from general practitioners.
Among the 58 cases, the mothers of 10 infants (17%) had received a pertussis vaccine during pregnancy. For controls, the mothers of 39 infants (71%) had received the vaccine. After adjustment for sex, geographical area and birth period, the vaccine efficacy was 93% (95% CI, 81-97).
“The observed [vaccine efficacy] is likely to be a combination of the direct effect of transplacental antibody transfer from mother to infant, and the indirect effect of protecting the mother from pertussis and potentially reducing household transmission and preventing infant infection,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.