Researchers Find Benefits for Newborns of COVID-19–Vaccinated Mothers

Mothers that were vaccinated against COVID-19 during pregnancy were not connected with increased risks in newborn infants, according to findings published in JAMA. The study was conducted by Swedish and Norwegian researchers that included almost 200,000 newborns. The results showed a decreased chance of serious complications among babies that were born from vaccinated mothers.

Image credit: milanmarkovic78 | stock.adobe.com

“We made several attempts to explain this finding. A direct vaccine effect is unlikely. Previous studies have shown that the vaccine does not cross the placenta and that it cannot be found in umbilical cord blood," said Mikael Norman, professor of pediatrics and neonatology at the Department of Clinical Science, Intervention and Technology, Karolinska Institute and first author of the study, in a press release.

Data were used from national registers in Sweden and Norway. The researchers included births from gestation at week 22 and forward.

Approximately 196,470 newborns were included in the study. Among the newborns, 43% of mothers were vaccinated with one or more doses of a mRNA vaccine to protect against COVID-19. According to the study authors, nearly 80% of mothers received the Pfizer/Biontech immunization and nearly 20% received the Moderna vaccine.

The first baby included in the study was born June of 2021 and the last baby was born January of 2023, according to study authors. Follow ups were conducted on each of the infants for 1 month after birth or throughout the period they stayed in a neonatal unit.

The researchers created 7 separate subgroup evaluations among the women and babies. The results found that the mortality rate was only half as high in infants that mothers were previously vaccinated, according to study authors.

“No matter how we look at it, the finding remains and therefore, we cannot say what the lower risk of death among infants of vaccinated women relates to," said Norman, in a press release.

The study authors noted that 15 neonatal complications were analyzed in the study. In this analysis, the researchers reported additional lower risks in other serious complications that could occur in infants, among mothers that were vaccinated.

"We saw lower rates of cerebral hemorrhages and hypoxia-ischemic conditions of the brain in the newborns of vaccinated than in babies of unvaccinated in pregnancy, while the incidence of other bleedings, blood clots, or inflammation in various organ systems did not differ between the groups," said Norman, in a press release.

Norman noted that the findings could aid health care providers' knowledge when recommending the vaccine for women who could become pregnant in the future.

"COVID-19 is still present in society and is probably something we will have to deal with for a long time. It is therefore very important for the one hundred thousand women who become pregnant every year in Sweden, and the 130 million in the world, to know that vaccination with mRNA-vaccines against COVID-19 is safe for their babies. We found no increased risks, if anything, infants to vaccinated women had lower risks for some severe outcomes,” said Norman, in a press release.

Reference

Covid vaccine for pregnant women safe for newborn infants. EurekAlert!. News release. February 6, 2024. Accessed February 8, 2024. https://www.eurekalert.org/news-releases/1033094.