Association Between Maternal Pertussis Vaccination During Pregnancy and Early Childhood Health Outcomes

Abstract

Background: Little is known about whether there are any longer-term adverse health effects in children following Tdap (tetanus, diphtheria, and acellular pertussis) vaccination during pregnancy. Objective: To assess the association between maternal Tdap vaccination during pregnancy and risk of the following early childhood adverse health outcomes: (1) infections (upper and lower respiratory tract infections, gastrointestinal infections, and otitis media), (2) pediatric asthma, (3) neoplasm, (4) vision or hearing loss, and (5) urgent and in-patient health services utilization. Methods: This retrospective cohort study used multiple linked health administrative databases in the province of Ontario, Canada containing vaccine information in mothers and information on health outcomes in their children up to age 6 years. Infants exposed to prenatal Tdap were matched 1:5 with unexposed infants and outcomes were compared using hazard ratios and incidence rate ratios. Results: No significant adverse associations between prenatal Tdap and our study outcomes were observed. Inverse associations were found with upper respiratory infections (adjusted incidence rate ratio [aIRR]: 0.96, 95% CI: 0.93-0.99), lower respiratory infections (aIRR: 0.93, 95% CI: 0.89-0.98), gastrointestinal infections (aIRR: 0.88, 95% CI: 0.82-0.94), and urgent and in-patient health service utilization (aIRR: 0.95, 95% CI: 0.94-0.97). Conclusions: Our findings support the long-term safety of Tdap administration in pregnancy.