Women who have had Covid-19 can pass protective antibodies on to their babies, according to a new study published today.
The research from the American Journal of Obstetrics and Gynecology looked at blood samples from 88 women who gave birth at a hospital in New York between March and May 2020. At the time, New York had staggeringly high levels of people infected with the SARS-CoV2 coronavirus and was considered one of the global epicenters of the virus.
All of the women tested had Covid-19 antibodies in their blood indicating a prior infection, although 58% of the women experienced no symptoms. Crucially, 78% of the babies born to the women in the study also had detectable antibodies in blood samples taken from their umbilical cord. All of the babies were tested for Covid-19 at birth and there was no evidence that any of them had actually had an active Covid-19 infection, indicating that the antibodies had been transferred from the mother, via the placenta.
The study also found that mothers who had symptomatic infections with Covid-19 had higher antibody levels than those who were asymptomatic. This trend was also reflected in their babies, with babies from asymptomatic mothers having lower antibody levels than those from mothers who had experienced Covid-19 symptoms.
There has been a lot of discussion as to whether pregnant women should get vaccinated against Covid-19 and Pfizer/BioNTech, one of the major manufacturers of Covid-19 vaccines, recently started a clinical trial to assess the vaccination in pregnant women. The CDC has also issued advice for pregnant women considering the vaccine, following evidence that pregnant people are at a higher risk of severe Covid-19 outcomes than similarly aged women who are not pregnant, including illness that results in ICU admission, mechanical ventilation, and death.
It isn’t yet known whether the antibodies that are produced by Covid-19 vaccination will be passed on from mothers to babies in the same way, but the study authors are hopeful that this will be the case.
“Since we can now say that the antibodies pregnant women make against Covid-19 have been shown to be passed down to their babies, we suspect that there’s a good chance they could pass down the antibodies the body makes after being vaccinated as well,” said Dr. Yawei Jenny Yang, an assistant professor of pathology and laboratory medicine at Weill Cornell Medicine and the study’s senior author.
The study implies that this transmission of antibodies between mother and baby could help to protect them from future infections with the SARS-CoV2 coronavirus. However, the authors also caution that it isn’t yet known exactly how protective these antibodies might be in the mothers or the babies and how long any immunity might last.
Dr. Yang and colleagues are leading further investigations in pregnant and breastfeeding women who receive the vaccine to look at the antibody response in those groups after vaccination. They hope that this information will help guide maternal vaccination strategies moving forward.