Vaccinated mothers can transfer coronavirus antibodies through breast milk, studies suggest

Although the current COVID19 vaccines have not been approved for infants, it turns out there may be another way babies can get antibodies in their system: through the breast milk of mothers who have been vaccinated themselves.

Several recent studies have shown that antibodies can be passed from mothers to their infants through breastfeeding.

Previous studies looked at mothers who were infected with COVID-19 themselves, but emerging data has also looked at whether vaccinated mothers may be able to pass along antibodies.

One small study, published at the end of March in the American Journal of Obstetrics and Gynecology, tracked five women for a period of several months in order to measure how long antibodies might be present in breast milk after vaccination.

By looking at samples of breast milk taken at different stages, they found that there were still protective antibodies in the women’s breast milk 80 days after they had been vaccinated with the Pfizer vaccine.

“Our study showed a huge boost in antibodies against the COVID-19 virus in breast milk starting two weeks after the first shot, and this response was sustained for the course of our study, which was almost three months long,” Jeannie Kelly, first author and assistant professor of obstetrics and gynecology at the Washington University School of Medicine, said in a press release Tuesday. “The antibodies levels were still high at the end of our study, so the protection likely extends even longer."

Although it’s impossible to know definitively if the antibodies would prevent an infant from contracting COVID-19, the level of antibodies in the breast milk was found to reach “immune-sufficient levels” a little over two weeks after the first shot, the release stated.

“So, getting vaccinated while breastfeeding not only protects mom, but also could protect the baby, too, and for months,” Kelly said.

Misty Good, an assistant professor of pediatrics at Washington University and senior author of the study, said in the release that although they are limited by the small number of participants, the research still provides “encouraging news.”

“Our paper is the first that has shown COVID-19 antibodies persist in breast milk for months following the mother’s vaccination,” she said.