Health Outcomes in Young Children Following Pertussis Vaccination During Pregnancy

Abstract

BACKGROUND AND OBJECTIVES: Maternal immunization with tetanus, diphtheria, and acellular pertussis vaccine (Tdap) is routinely recommended in many countries as a strategy to protect young infants against severe pertussis infection; few studies have assessed whether prenatal exposure to the vaccine is associated with any longer-term adverse health effects in children. We evaluated the long-term safety of exposure to Tdap vaccination during pregnancy.METHODS: Population-based retrospective cohort study conducted in Ontario, Canada using multiple linked province-wide health administrative databases. All live births between April 2012 and March 2017 were included, and children were followed for up to 6 years to ascertain study outcomes. Children exposed to prenatal Tdap were propensity score matched to unexposed children at a 1:5 ratio. Tdap vaccination during pregnancy was ascertained by using vaccine-specific fee codes. Immune-related (infectious diseases, asthma) and nonimmune-related (neoplasm, sensory disorders) outcomes and a nonspecific morbidity outcome (urgent or inpatient health service use) were evaluated from birth to end of followup.RESULTS: Of 625 643 live births, 12 045 (1.9%) were exposed to Tdap in utero. There were no significant increased risks of adverse childhood outcomes and prenatal Tdap exposure; however, we observed inverse associations (adjusted incidence rate ratio [95% confidence interval]) with upper respiratory infections (0.94 [0.90-0.99]), gastrointestinal infections (0.85 [0.79-0.91]), and urgent and inpatient health service use (0.93 [0.91-0.96]).CONCLUSIONS: Exposure to Tdap vaccination in pregnancy was not associated with any increased risk of adverse health outcomes in early childhood, supporting the long-term safety of Tdap administration in pregnancy.WHAT'S KNOWN ON THIS SUBJECT: Maternal immunization with tetanus, diphtheria, and acellular pertussis vaccine (Tdap) provides infants with passive immunity against pertussis during their first months of life; however few researchers have assessed longer-term health outcomes in young children.WHAT THIS STUDY ADDS: Exposure to Tdap during pregnancy was not associated with any increased risk of adverse health outcomes or urgent and inpatient health service use in early childhood, supporting the long-term safety of Tdap administration in pregnancy.

Safety and Clinical Benefits of Adacel® and Adacel®-Polio Vaccination in Pregnancy: A Structured Literature Review

“…In particular, Tdap vaccination in pregnancy had no effect on the incidence of autism spectrum disorder [ 54 ], attention-deficit hyperactivity disorder [ 55 ], infant growth problems [ 59 ], or hospitalization and death rates in the first 6 months of life [ 68 ]. Additionally, one study showed an inverse association of Tdap vaccination in pregnancy with infant upper respiratory infection, gastrointestinal infection, and urgent/inpatient healthcare use [ 62 ], and, in another study, the incidence of respiratory hospitalization was shown to be higher in infants without Tdap vaccination in pregnancy [ 68 ]. No cases of pertussis illness occurred in mothers or infants according to the study reports.…”

“…These VE data support the many national recommendations for Tdap vaccination in pregnancy to prevent hospitalization and death from pertussis in young infants. Additionally, one study showed that infants without Tdap vaccination in pregnancy were more likely to be hospitalized due to respiratory symptoms [ 68 ], and another showed an inverse relationship between Tdap vaccination during pregnancy and infant upper respiratory tract infections [ 62 ]. The impact of vaccination with Adacel and Adacel-Polio during pregnancy continues through the first year of life, even after the infant’s primary DTaP vaccination series.…”

Impact of national recommendations for routine pertussis vaccination during pregnancy on infant pertussis in Ontario, Canada: a population-based time-series study

“…Antenatal pertussis immunization is an effective intervention for mitigating the burden of severe pertussis illness in young infants, with estimates of vaccine effectiveness ranging from 36 to 90% in several studies [26][27][28][29][30][31][32][33][34]. Further, antenatal Tdap immunization is safe, with multiple studies finding no association between vaccination and adverse fetal or neonatal outcomes [12,[34][35][36][37]]. Yet, despite supportive evidence, several studies have documented suboptimal uptake of maternal pertussis immunization [38][39][40][41][42].…”

Worries, beliefs and factors influencing perinatal COVID-19 vaccination: a cross-sectional survey of preconception, pregnant and lactating individuals

“…Infertility was a major concern, and it is important for governments and professional associations to quickly address misinformation circulating online and on social media with scientific evidence. Many respondents were concerned with fetal growth and development, and there are now many studies available for other vaccines showing that vaccination during pregnancy is not associated with long-term adverse health consequences in children [28][29][30][31]. These should be shared widely and used in knowledge dissemination campaigns with HCPs and our communities.…”