No increased risks for babies, and for some serious neonatal complications lower risks. This is the result of the largest study to date on the safety of newborn babies whose mothers were vaccinated against COVID-19 during pregnancy. The study is a collaboration between Swedish and Norwegian researchers and is published in the journal JAMA.
COVID-19 vaccination in pregnancy was not associated with any increased risks in newborn infants. On the contrary, the study of nearly 200,000 newborns in Sweden and Norway showed that babies born by women who chose to be vaccinated were less likely to suffer serious complications, including death. The mortality rate was only half as high in babies whose mothers had been vaccinated.
"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," says Mikael Norman, professor of pediatrics and neonatology at the Department of Clinical Science, Intervention and Technology, Karolinska Institutet and first author of the study.
Instead, the researchers have adjusted for several background factors that were unevenly distributed in the two groups of women. They also conducted seven different subgroup analyses of women and newborns.
"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," says Mikael Norman.
