COVID Shot While Pregnant Limits Severe Cases in Infants Says CDC

2 min read

Sept. 29, 2023 – Getting a COVID-19 vaccine during pregnancy significantly reduces the chance that a baby will be hospitalized for COVID-19, new data shows.

The study from the CDC found that vaccines were 54% effective at protecting infants from COVID-19 hospitalization in the first 3 months of life, and 35% effective at protecting babies from ages 3 months through 5 months old. Infants can be vaccinated against COVID-19 starting at 6 months old. 

Infants who were hospitalized with COVID-19 whose mothers were unvaccinated were more likely to need help breathing, compared to infants whose mothers had been vaccinated.

For the study, researchers analyzed data for 716 babies hospitalized between March 2022 and May 2023. Among the babies in the study, 377 were hospitalized with COVID-19. Mothers were considered vaccinated if they’d had at least two COVID vaccines, one of which was given during pregnancy. All other mothers of babies in the study were unvaccinated.

Vaccinated mothers pass antibodies against COVID-19 through the placenta to the fetus. The authors noted that a limitation of the study was that prior infection of mothers was not analyzed, including among unvaccinated mothers. They also said it is possible that “infection-induced antibodies could provide some protection against infant COVID-19–related hospitalization.”

“Maternal vaccination during pregnancy provides some protection against COVID-19–related hospitalizations among infants, particularly those aged less than 3 months,” the authors wrote. “Expectant mothers should remain current with COVID-19 vaccination to protect themselves and their infants from hospitalization and severe outcomes associated with COVID-19.”

Previous research has shown that having COVID-19 during pregnancy increases the risk of preterm birth and stillbirth, and that pregnant people are at an increased risk of experiencing a severe case of the illness. 

COVID vaccination rates among pregnant women range from 16% to 27%, according to the CDC. That’s in comparison to survey data published this week by the agency that showed 47% of pregnant women reported getting a flu shot during the past flu season. Among women who had a live birth, 54% reported getting the Tdap vaccine, which can protect babies from pertussis (sometimes called “whooping cough”).

The professional group for obstetricians and gynecologists “strongly recommends” that all pregnant women get vaccinated for COVID-19 and get the latest booster shot, adding that the vaccines are safe during pregnancy and breastfeeding. The American College of Obstetricians and Gynecologists notes that antibodies from the vaccine are passed from mother to baby through the placenta during pregnancy and may be passed to the baby through breast milk, as well. 

Researchers wrote that they were not able to analyze the timing of COVID vaccination during pregnancy, specific brands or formulations of vaccines, nor whether vaccine effectiveness varied against different subvariants of the SARS-CoV-2 virus. They also noted that the results could have been influenced by “maternal characteristics or protective behaviors,” and that the impact of breastfeeding, which may transfer antibodies to a baby, also could not be assessed due to incomplete data for some mothers.