The infants of mothers who completed two doses of either the Moderna or Pfizer/BioNTech coronavirus vaccines during pregnancy had about a 60% reduced risk for being hospitalized with Covid-19 in the first six months of their lives, a new study finds.
The study, published by the US Centers for Disease Control and Prevention on Tuesday, suggests that getting vaccinated against Covid-19 during pregnancy might not only protect the mother, but her baby, too. In addition, that protection appeared to be higher among infants whose mothers were vaccinated later in pregnancy.
The researchers — from the CDC and other US institutions and universities — wrote in the new study that Covid-19 antibodies likely could be transferred across the placenta from a mother to the baby during pregnancy and “might provide protection to infants.”
The study included data on 379 hospitalized infants younger than 6 months — 176 with Covid-19 and 203 without Covid-19, but hospitalized for other reasons — at 20 pediatric hospitals in 17 states between July of last year and mid-January of this year. The mothers of the infants were asked about their Covid-19 vaccination history, including the number of doses completed and whether a dose had been received during pregnancy.
The report found that Covid-19 vaccination during pregnancy reduced the risk of infant hospitalization with Covid-19 by 61%. The effectiveness after completing vaccination early in pregnancy was 32%, and later in pregnancy was 80%.
The researchers found that overall, 15.9% of the mothers of infants with Covid-19 were vaccinated during pregnancy compared with 32% of the mothers of infants without Covid-19.
The data showed that 10.3% of the mothers of infants with Covid-19 had been vaccinated early during pregnancy and 5.7% were vaccinated in late pregnancy, compared with 15.9% of the infants without Covid-19 were vaccinated in early pregnancy and 21.6% in late pregnancy.
Covid-19 vaccination rates among US pregnant women have been improving, Meaney-Delman told CNN, but they still are not where she would like them to be.
She added that there are no risks for pregnant women from vaccination — “no increased risk of miscarriage associated with vaccination” and no association with infertility.
The study did not include data on vaccine effectiveness of booster shots, or on mothers who were vaccinated before pregnancy.
But for women who already were vaccinated and boosted before pregnancy, that helps protect against the adverse outcomes that are associated with having Covid-19 during pregnancy, Meaney-Delman said. “Covid during pregnancy has been well associated with preterm birth — so babies are premature, which obviously has potential risks for them — and an increased risk of stillbirth.”