If a woman is infected with Covid-19 during pregnancy, can her baby gain immunity to the virus in the womb?
The study, published today in the journal JAMA Pediatrics, suggests that the mother’s new crown antibodies can cross the placenta, potentially protecting the fetus from infection.
The researchers analyzed blood samples from more than 1,470 pregnant women, and 72 of the 83 women who had antibodies against Novel coronavirus at delivery also had antibodies in their newborns.
This suggests that these babies have acquired this passive immunity.
The antibodies that cross the placenta are immunoglobulin G or IgG antibodies, which are produced a few days after infection with novel coronavirus and offer protection in the body.
None of the infants in the study had immunoglobulin M (IgM) antibodies, which are usually detected shortly after infection, suggesting that the infants were not infected with novel coronavirus.
The researchers said the number of antibodies passed to the baby largely depended on the type and amount of antibodies in the mother’s body, as well as how long the mother had been infected with novel coronavirus during pregnancy.
“The longer the time between maternal infection and delivery, the greater the likelihood of antibody transfer.”
The association held true for mothers infected with novel coronavirus with or without symptoms, said study authors Dr. Karen Popporo and Dr. Scott Hunsley of the Perelman School of Medicine at the University of Pennsylvania.
Transferred antibodies may provide protection in newborns, but it remains to be determined what levels and types of antibodies are needed to protect newborns from novel coronavirus infection and how long these antibodies can persist in newborns, the researchers note.
Another big question is how well a transferred antibody “neutralizes” a novel coronavirus, an antibody’s ability to stop the virus from infecting a cell.
“By studying the natural transfer of antibodies after Novel coronavirus infection, we can investigate whether vaccinating pregnant women provides similar protection for newborns,” said Dr. Flo Munoz Rivas, associate professor of pediatric infectious diseases at Baylor College of Medicine in Houston, United States.