COVID Antibodies Found In Breastmilk Of Vaxxed And Previously Infected Moms

by Christina Marfice
Jamie Grill/Getty

A new study showed that new moms had COVID antibodies in their breast milk if they were vaccinated, but also if they were previously infected

As we continue to learn more about COVID-19 and how to protect ourselves — and future generations — from the virus, researchers at the University of Rochester Medical Center have discovered good news about new moms who have protection from COVID, either from vaccination or from a previous infection: They may be able to pass on important antibodies through their breast milk that will help protect their babies.

The study, published recently in JAMA Pediatrics, analyzed breast milk from 77 mothers — 47 who had been infected with COVID previously, and 30 who received the vaccine. Researchers wanted to first see if their breast milk contained any antibodies at all, and then analyze the level of antibodies in breast milk over time.

The study found that the mom who had had a COVID-19 infection had high levels of Immunoglobulin A (IgA) antibodies, while the mom who had received COVID vaccines had high levels of Immunoglobulin G (IgG) antibodies. Both antibodies can help protect us against infection, severe disease, and death from COVID.

The study also showed that antibodies were still present in the breast milk after three months, which is the longest time shown in a study. Previous studies have found antibodies in breast milk, but scientists still aren’t sure how long those antibodies will remain there, after either infection or vaccination.

“It’s one thing to measure antibody concentrations, but it’s another to say that antibodies are functional and can neutralize the SARS-CoV-2 virus,” Bridget Young, Ph.D., an assistant professor in the Division of Pediatric Allergy and Immunology at URMC, said. “One of the exciting findings in this work is that breast milk from both mothers with COVID-19 infection, and from mothers receiving mRNA vaccination contained these active antibodies that were able to neutralize the virus.”

This study also supports scientists’ theories that while protection from COVID vaccines is robust, the best protection comes from both being vaccinated, and having had a COVID infection.

There are still lingering questions, though. The biggest one may be this: Do the antibodies in breast milk help protect nursing babies from COVID infections? Researchers say the evidence is promising, but not conclusive just yet.

“The study does not imply that children would be protected from illness,” the study’s co-author, Kirsi Jarvinen-Seppo, said. “And breast milk antibodies may not be a substitute for vaccination for infants and children, once approved.”