Drs. Natalie Cvijanovich and Matt Zinter worked with the CDC to analyze the level of protection that maternal vaccination during pregnancy provides infants.

Vaccination During Pregnancy Protects Infants from COVID-19

Researchers from UCSF’s Department of Pediatrics Natalie Cvijanovich, MD, and Matt Zinter, MD, in the Division of Critical Care recently worked with the CDC to analyze how effective the protection that maternal vaccination provides infants against COVID-19. Their recent publication in the New England Journal of Medicine used data from over 500 infants hospitalized for COVID-19 and found that children born to mothers who were vaccinated during pregnancy were less likely to get seriously ill than children born to unvaccinated mothers.

Considering that infants younger than 6 months account for nearly half of hospitalizations for children aged 0-4 with a confirmed COVID-19 case, affirming ways for parents to protect their at-risk newborns is an essential step to mitigate the continued impact from COVID-19. Maternal vaccination has long been proven effective for vaccine-preventable diseases such as influenza and pertussis, and it’s well-documented that COVID antibodies transfer to the infant during incubation.

The data from these 500 case infants reveal a trend where infants born with maternal vaccination were significantly less likely to become seriously ill if they were infected with COVID-19 than those whose mothers were not vaccinated against COVID-19. These infants born to mother who got vaccinated during pregnancy accounted for 16% of the COVID-related hospitalizations out of the 500 case infants, but only 10% of ICU admissions.

Infants born to vaccinated mothers also were less likely to require very aggressive interventions, including invasive breathing assistance, oxygenation machine use and vasoactive drug use to maintain cardiovascular function. Tragically, 2 infants included in the study passed away; both were born to unvaccinated mothers.

UCSF Department of Pediatrics assistant professor Mary Prahl, MD, wrote about her experience with pregnancy in 2020, in the midst of her research career focused on how infectious diseases affect pregnant people and their infants.  

“Many pregnant people have had questions on the safety and benefit of COVID-19 vaccination in pregnancy,” Prahl says. “Questions of ‘How will this affect my baby?’ and ‘Are there enough studies on vaccination in pregnancy?’"

The CDC has now gathered evidence showing that vaccines are safe for pregnant people and their infants. Prahl says that Cvijanovich’s study is “one of the first to show the benefit of vaccination during pregnancy for the baby—protection against COVID-19 in the first months of life. This study provides some reassurance to pregnant individuals that they are helping their babies in those vulnerable first few months by getting vaccinated during pregnancy.”

Current data in the United States shows that 30% of pregnant people in the United States are unvaccinated and nearly 30% of women who are pregnant believe one piece of misinformation about the COVID-19 vaccine and pregnancy.

As the CDC states that a COVID-19 infection while pregnant has an increased chance of becoming serious and increases the risk of pregnancy complications, Cvijanovich and her co-authors state that their study supports the CDC’s recommendation for individuals to stay up to date with their COVID-19 vaccines, and that unvaccinated pregnant people should strongly consider getting vaccinated not only to protect themselves but also to protect their newborn baby.