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Study: Breast milk of moms vaccinated against COVID-19 contains protective antibodies for at least 80 days

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I AM: Breastfeeding support group

Kenia Mahdi, 28, of St. Louis, nurses her 5-month old daughter, Ruqayyah, during an I AM: Breastfeeding support group meeting at the Ferguson Public Library on May 24, 2016 in Ferguson. Photo by Michael Thomas

ST. LOUIS — A small study shows protective antibodies against COVID-19 are found in the breast milk of moms for at least 80 days following their vaccination.

“The antibodies levels were still high at the end of our study, so the protection likely extends even longer,” said Dr. Jeannie Kelly, assistant professor of obstetrics and gynecology at Washington University School of Medicine in St. Louis.

The study by Washington University was published March 30 in the American Journal of Obstetrics and Gynecology. Researchers measured levels of COVID-19 antibodies in breast milk before the mothers’ first dose of the two-dose Pfizer coronavirus vaccine and on a weekly basis for 80 days.

The research provides some of the first peer-reviewed evidence that breastfeeding confers a long-lasting immune response in the nursing infants and toddlers of vaccinated mothers, the university announced in a press release.

Other recent research has shown that COVID-19 vaccines generate antibodies in breast milk, but this is thought to be the first to track levels over an extended time, researchers said.

“Our paper is the first that has shown COVID-19 antibodies persist in breast milk for months following the mother’s vaccination,” said Dr. Misty Good, assistant professor of pediatrics at Washington University.

The study involved five mothers who provided frozen breast milk samples. The babies of the women ranged in age from 1 month to 24 months old.

The women’s breast milk contained elevated levels of the antibodies immediately following their first dose of vaccination, with antibodies reaching protective levels within 14 to 20 days.

The levels were sustained over the course of study, which was almost three months long.

“Our study is limited by a small number of participants, but the findings provide encouraging news about the potential immune benefit to breastfeeding infants after vaccination,” Good said.

Data is limited on the safety of COVID-19 vaccines in pregnant women, but based on how the vaccines works, they are unlikely to pose a risk, according to the U.S. Centers for Disease Control and Prevention.

Clinical trials that look at the safety of COVID-19 vaccines in pregnant women are underway. Vaccine manufacturers also monitor data from people in the clinical trials who received vaccine and became pregnant.

Evidence thus far shows the COVID-19 vaccine offers benefits for protecting both mother and child.

“We do know that COVID-19 infection is more severe during pregnancy and the main benefit of vaccination is to provide protection for moms before they become really sick, which can also be dangerous to their fetus,” said Kelly, who recommends pregnant and breastfeeding moms get vaccinated as soon as possible.

Almost 70,000 pregnant women have been vaccinated against COVID-19 with no evidence of harm, she said.

“We’re now seeing a cascade of new data that indicate maternal vaccines are also going to help protect babies — both through transfer of antibodies through the placenta during pregnancy and through the breast milk during lactation,” Kelly said. “This is information we didn’t have a few months ago and it’s really helping us better counsel our patients who are considering getting the vaccine.”

Photos: Families catch up on hugs, hand-holding and overdue holidays after vaccinations As vaccination rates climb and families — finally — feel like they can reunite after a year’s worth of spread-out socializing, drive-by birthday parades and Zoomed holidays. Loved ones are making up for lost time: throwing spring Thanksgiving feasts, huddling together over phones to scroll through a backlog of photos and, sometimes, just holding hands, sitting cheek-to-cheek and hugging each other tight.

Michele Munz • 314-340-8263 @michelemunz on Twitter


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