Study finds COVID vaccine for pregnant women safe for newborns

Results from the largest study to date on the safety of newborns whose mothers were vaccinated against COVID-19 during pregnancy show no increased risks to babies and, for some serious neonatal complications, greater risks. weak. The study is a collaboration between Swedish and Norwegian researchers and is published in the journal JAMA.

COVID-19 vaccination during pregnancy was not associated with any increased risk in newborns. On the contrary, a study of nearly 200,000 newborns in Sweden and Norway showed that babies born to women who chose to be vaccinated were less likely to suffer serious complications or even death. The mortality rate was half as high among babies whose mothers had been vaccinated.

“We have repeatedly tried to explain this result. A direct effect of the vaccine is unlikely. Previous studies have shown that the vaccine does not cross the placental barrier and cannot be found in cord blood umbilical”, explains Mikael Norman, professor of pediatrics and neonatology. at the Department of Clinical Sciences, Intervention and Technology at Karolinska Institutet and first author of the study.

Instead, the researchers adjusted for several contextual factors that were unequally distributed between the two groups of women. They also conducted seven analyzes of different subgroups of women and newborns.

“Whatever way we look at things, the observation remains and we therefore cannot say what the lower risk of death corresponds to in infants born to vaccinated women,” explains Mikael Norman.

The researchers used national registries from both countries and included 98% of all newborns of women who became pregnant after vaccines became available. All births from the 22nd week of gestation were included in the study. The first baby was born in June 2021 and the last in January 2023. All babies were followed for at least one month or as long as they were admitted to a neonatal unit.

In total, the study included 196,470 newborns, 48% of whose mothers had been vaccinated with one or more doses of an mRNA vaccine against COVID-19. Nearly 80% had received the Pfizer/BioNTech vaccine and just over 20% that of Moderna.

In addition to lower infant mortality, the researchers also found a significantly lower risk of two other serious complications among infants born to vaccinated mothers. In total, fifteen neonatal complications and conditions were studied.

“We found lower rates of cerebral hemorrhage and cerebral hypoxia-ischemia in vaccinated newborns than in unvaccinated babies during pregnancy, while the incidence of other bleeding, blood clots or inflammation in various organ systems did not differ between the groups.”, says Mikael Norman.

Even though the pandemic is over, the study and results are of great importance to health professionals who offer advice, to authorities who issue recommendations and, above all, to anyone who may become pregnant in the future. “future,” explains Mikael Norman.

“COVID-19 is still present in society and it is probably a problem that we will have to deal with for a long time. It is therefore very important for the hundred thousand women who become pregnant every year in Sweden and for the 130 million in the world., to know that vaccination with mRNA COVID-19 vaccines is safe for their babies. We found no increased risk, if anything, infants of vaccinated women had lower risks of certain serious consequences.