Newborns and early infants whose mothers received a maternal mRNA COVID-19 vaccine during pregnancy may be protected from different adverse outcomes, according to new data published in JAMA Pediatrics.1
COVID-19 vaccination is routinely recommended to pregnant women due to an increased risk of severe disease, but rates of vaccination in this population remain low. Although previous studies have examined associations between COVID-19 vaccines and adverse outcomes in pregnancy, a lack of data exists on safety outcomes for infants after the neonatal period.
“Many women feel nervous about receiving vaccines during pregnancy, but our study will hopefully provide some reassurance on the safety of COVID-19 vaccine during pregnancy for newborns and young infants,” Sarah Jorgensen, a pharmacist and lead author on the study, said in a release.2
A team of investigators from the Institute for Clinical Evaluative Science and the University of Toronto conducted a cohort study to examine if maternal mRNA COVID-19 vaccination during pregnancy is associated with adverse newborn and early infant outcomes. Data was gathered from the MOMBABY database, which includes multiple health administrative databases from Ontario, Canada, from May 1, 202, through September 2, 2022.
Infants were excluded if they had a gestational age of less than 20 weeks, a birth weight of less than 500 grams, if their mothers did not have insurance the year preceding birth, if they had incomplete birth records, or if they were born to mothers younger than 12 or older than 50.
The study cohort included 142006 infants, of which 85670 were born to mothers who received 1 or more COVID-19 mRNA vaccine doses during pregnancy. Data on 6-month follow up visits was also available for 112623 infants.
Investigators found that infants of vaccinated mothers had a lower risk of severe neonatal morbidity, neonatal death, and admission to neonatal intensive care units compared to infants of unvaccinated mothers. Results were largely unchanged when analyzed by number of vaccine doses during pregnancy, trimester of vaccination, vaccine product, and infant sex.
Additionally, there was no association between maternal vaccination during pregnancy and neonatal readmission, or 6-month hospital admission.
Study limitations include propensity scores being limited to variables available in study databases, a lack of information on maternal body mass, tobacco use, or breastfeeding, and analyses being restricted to live births.
“Our results were consistent across the number of doses someone received during pregnancy, the trimester in which they were vaccinated, and the vaccine product they received, which gives us more confidence that there is no increase in the adverse newborn and infant outcomes we assessed,” said Jorgensen.