Association Between COVID-19 Vaccination During Pregnancy and Safety Among Infants

Vaccination during pregnancy prevents disease in both the pregnant woman and infant via transplacental antibody transfer which may interfere with infant immune response to early childhood vaccination. Data on safety of COVID-19 vaccination during pregnancy in relation to non-targeted infant infections are lacking.

We conducted a retrospective cohort study of pregnancies from May 17, 2020, through February 15, 2021, across eight integrated healthcare systems in the Vaccine Safety Datalink to evaluate receipt of COVID-19 vaccination during second or third trimester of pregnancy on medically attended encounters for infections among infants up to 6 months. Adjusted incidence rate ratios (aIRRs) with 95% confidence intervals were estimated, controlling for potential confounders using inverse probability of treatment weighting.

Among 42 940 pregnancies, 14 762 (34.4%) were exposed to COVID-19 vaccination during second or third trimester of pregnancy. COVID-19 vaccination during second or third trimester was not associated with an increase in non-targeted infant medically attended respiratory infections (aIRR 0.86, 95% CI 0.77, 0.95), including respiratory syncytial virus (RSV) (aIRR 0.78, 95% CI 0.65, 0.93) and was not associated with infant bloodstream (aIRR 1.03, 95% CI 0.77, 1.37) or meningeal (aIRR 0.54, 95% CI 0.19, 1.56) infections up to 6 months of life.

We found no increased risk for non-targeted medically attended infant respiratory infections and no association with bloodstream or meningeal infections from birth to 6 months of life following COVID-19 vaccination during second or third trimester of pregnancy. These findings support COVID-19 vaccination safety during pregnancy on the risk of non-targeted infant infections.