The Effect of Maternal Pertussis Vaccination on Neonatal Health Outcomes in the Dutch Pregnancy Drug Register

BACKGROUND: The currently high pertussis-related morbidity and mortality among infants has led to increased international attention for pertussis vaccination during pregnancy. We studied the safety of maternal pertussis vaccination in the Netherlands with respect to neonatal health. METHODS: Data from the cohort the Dutch Pregnancy Drug Register were used. Pregnant participants self-reported their pertussis vaccination and the health outcomes of their offspring. Participants with a singleton live birth ≥ 24 weeks gestation were included. Using log-binomial regression analysis and correction for confounders, we studied the risk of maternal pertussis vaccination on various neonatal health outcomes. Moreover, we compared differences in health outcomes between second and third trimester vaccinations. RESULTS: The study population included 10,280 participants (74.8% vaccinated against pertussis during pregnancy and 25.3% not). The adjusted risk ratio (RR) was: 1.01 (95% confidence interval [CI]: 0.82-1.23) for small for gestational age; 0.90 (95% CI: 0.73-1.11) for large for gestational age; 0.86 (95% CI: 0.59-1.25) for low birth weight; 1.06 (95% CI: 0.90-1.25) for neonatal health problems, and 0.68 (95% CI: 0.47-0.99) for infant hospitalization due to (suspicion of) infection. Also for the secondary outcomes neonatal death, low Apgar score, and neonatal intensive care unit admission, no increased risk after maternal pertussis vaccination was observed. There was no difference in neonatal health outcomes between second and third trimester pertussis vaccinations. CONCLUSIONS: The maternal pertussis vaccination did not increase the risk of several adverse neonatal health outcomes, confirming the safety of pertussis vaccination during pregnancy with respect to neonatal health outcomes.