Safety of diphtheria-tetanus-acellular pertussis (DTaP) vaccination during pregnancy in mothers and infants: The Shizuoka Study

BACKGROUND: For pregnant women, diphtheria-tetanus-acellular pertussis (DTaP) vaccine is available in Japan but rarely administer during pregnancy. The present study aimed to evaluate the safety of DTaP vaccine given to pregnant women in a retrospective, cohort study. METHODS: Consecutive pregnant women who had received prenatal checkups at 28-31 weeks' gestation between December 2020 and December 2022 were included. Information on vaccination status, maternal and infant outcomes were collected from medical records. The incidence proportions of maternal safety outcomes including pregnancy complications and delivery mode, and of infant safety outcomes including preterm birth, low birth weight, and congenital anomalies were compared between vaccinated and unvaccinated women. RESULTS: A total of 648 individuals were analyzed (470 vaccinated and 178 unvaccinated). There were no significant differences in the frequency of pregnancy complications after enrollment (2% of vaccinated, 2% of unvaccinated) or fetal abnormalities (0·2% of vaccinated, 1% of unvaccinated). All newborns delivered at the clinic were live births, and the delivery mode was similar between groups. No significant differences were observed in infant outcomes including preterm birth, low birth weight, and congenital anomalies between vaccinated and unvaccinated mothers. CONCLUSIONS: DTaP vaccination during pregnancy was not associated with adverse maternal or infant safety outcomes.