Vaccinated Mothers’ Breast Milk Contain Antibodies Helpful for Infants Amid COVID-19 Spread

The breast milk of lactating mothers vaccinated against COVID-19 contains a significant supply of antibodies that may help protect nursing infants from the illness, according to new research from the University of Florida.

Infants greatly benefit from breast milk due to their undeveloped immune system

“Our findings show that vaccination increases antibodies against SARS-CoV-2 — the virus that causes COVID-19 — in breast milk, implying that vaccinated mothers can pass on this immunity to their babies,” said Joseph Larkin III, Ph.D., senior author of the study and an associate professor in the UF/IFAS department.

Because their immune systems are undeveloped at birth, infants have a hard time fighting off illness by themselves. Some vaccinations are also ineffective in neonates because they are too immature, according to Josef Neu, M.D., a co-author of the study and professor of pediatrics at the University of Florida College of Medicine’s division of neonatology.

Breast milk helps nursing women to give “passive immunity” to their children during this sensitive phase, according to Neu. “Consider breast milk as a toolbox with a variety of tools that assist the child in preparing for life. Vaccination provides another option to the arsenal, one that has the potential to be particularly effective in avoiding COVID-19 infection “Neu remarked. “Our findings clearly imply that vaccinations can help protect both mom and baby, which is yet another compelling reason for pregnant or lactating women to be vaccinated,” says the researcher. When the Pfizer and Moderna vaccines were initially made accessible to health care professionals in December 2020 and March 2021, the research was undertaken.

Researchers enlisted the help of 21 breastfeeding health-care professionals who had never been exposed to COVID-19 before. The mothers’ breast milk and blood were taken three times by the study team: before immunization, after the first dosage, and after the second dose. NDTV reports the researchers “saw a robust antibody response in blood and breast milk after the second dose — about a hundred-fold increase compared with levels before vaccination … These levels are also higher than those observed after natural infection with the virus.”

Vivian Valcarce, M.D., a resident in the UF College of Medicine’s department of pediatrics, division of neonatology writes in their publication in Nature Magazine vaccinating mothers to protect babies is nothing new, and that expectant mothers are typically vaccinated against whooping cough and flu already because these can be serious illnesses for infants. She continues, explaining how “babies can also catch COVID-19, so routine vaccination of mothers against the virus could be something we see in the future” In light of this, the study team is continuing to look into how COVID-19 antibodies gained by immunization protect newborns who drink breast milk.

The research isn’t over yet, there is plenty more to explore

As Larkin explained in the publication, “we want to determine if children who are fed breast milk that has these antibodies acquire their own protection against COVID-19.” And we want to know more about the antibodies themselves, such as how long they stay in breast milk and how well they neutralize the virus. Stafford also emphasizes how much they “are learning about breast milk and all its benefits, and that’s what makes this research so fascinating — not just for us scientists but for non-scientists, too.”

Neu also is excited to see where things go, hoping for more simultaneous studies conducted around the world that also show antibodies in the breastmilk of vaccinated mothers, some of which are already underway. Neu says that this rise to the surface for their research validates a growing body of evidence.