Pregnant mothers’ antibodies to SARS-CoV-2 transfer to their fetuses

Antibodies to the SARS-CoV-2 coronavirus in the blood of pregnant women cross the placenta efficiently, and are found at similar concentrations in the blood of their newborns, according to a large study from researchers at the Perelman School of Medicine.

Pregnant person sits on a seat on public transit wearing a face mask.

The findings, reported JAMA Pediatrics, suggest that mothers who have had COVID-19, or asymptomatic exposure to the coronavirus, can, through this antibody transfer, provide some protection against the virus to their newborns. The authors hypothesize that this may have implications for COVID-19 vaccines.

The researchers tested blood samples from 1,471 women and their newborns for the presence of antibodies to SARS-CoV-2, and observed that 83 of the women had significant levels of SARS-CoV-2-specific antibodies. The vast majority (87%) of the newborn babies of these women also had significant levels of SARS-CoV-2-specific antibodies in samples of umbilical cord blood drawn at birth. The study found no evidence that the antibodies were due to fetal infection, indicating that it is likely the antibodies crossed the placenta from the mother’s blood to the fetal circulation.

“This transfer appears to be pretty efficient,” says study co-senior author Karen Puopolo, a neonatologist at Children’s Hospital of Philadelphia, an associate professor of pediatrics at the Perelman School of Medicine and chief of the Section on Newborn Medicine at Pennsylvania Hospital. “In some of the cases, the newborn’s blood concentration of SARS-CoV-2 antibodies was even higher than the mother’s.”

Read more at Penn Medicine News.