COVID-19 vaccine exposure in utero not linked to adverse neonatal outcomes

Pregnant women were not included in the preauthorization trial for the Pfizer/BioNTech vaccine for COVID-19, which led to conflicting advice on whether they should receive the vaccine. Worries about the effect that the vaccine might have on the child is one of the most common reasons an expectant person might give when declining to get it. A new investigation offers some need information on whether prenatal exposure to the vaccine was linked to adverse outcomes at birth and during the first months of life.¹

The investigators ran a population-based cohort study that included all singleton live birth between March and September 2021 that occurred within a large state-mandated health care organization in Israel that encompasses a quarter of the Israeli population. Primary outcomes at birth for the study were preterm birth and being small for gestational age. Outcomes following birth included inpatient hospitalizations, congenital anomalies, and all-cause death.

There were 24,288 newborns included in the cohort, with 96% born at ≥37 weeks’ gestation. Within this group, 16,697 were exposed to a maternal COVID-19 vaccine in utero, 2135 in the first trimester and 9364 in the second trimester. The median follow-up period was 126 days for infants exposed to vaccination and 152 days among newborns who were not. The investigators did not note a significant difference in the rate of preterm birth between exposed and unexposed newborns (risk ratio [RR] = 0.95; 95% CI, 0.83-1.10) and no differences were noted for small for gestational age (RR = 0.97; 95% CI, 0.87-1.08). Among the after birth outcomes, no significant difference were noted as well: all-cause neonatal hospitalizations (RR = 0.99; 95% CI, 0.88-1.12), postneonatal hospitalizations after birth (RR = 0.95; 95% CI, 0.84-1.07), congenital anomalies (RR = 0.69; 95% CI, 0.44-1.04), or infant mortality over the study period (RR = 0.84; 95% CI, 0.43-1.72).

The investigators concluded that there was no evident difference between the offspring of women who received the Pfizer/BioNTech vaccine and those of women who did not receive the vaccine. The findings bolster the evidence that supports women receiving the vaccine during pregnancy to protect not only themselves, but their newborns.

Reference

1. Goldshtein I, Steinberg D, Kuint J, et al. Association of BNT162b2 COVID-19 vaccination during pregnancy with neonatal and early infant outcomes. JAMA Pediatr. Epub ahead of print. doi:10.1001/jamapediatrics.2022.0001