• Posted March 6, 2024

Breastfeeding After COVID Booster Passes Protective Antibodies to Baby

There's more evidence bolstering the health effects of both breastfeeding and the COVID booster shot: Vaccinated, breastfeeding moms appear to pass COVID-fighting antibodies to their infants.

That's important, since babies under the age of 6 months aren't eligible for the COVID vaccine.

“We think that breast milk may play an important role in protecting the infants during the first six months of life from COVID,” concluded study co-author Dr. Vivian Valcarce.

Immunity could even save young lives, because "we continue to see babies being hospitalized from COVID-19 infections," Valcarce added.

She helped conduct the research while at the University of Florida (UF); she is now an assistant professor at the University of Alabama at Birmingham.

Prior studies have supported the notion that women passed along defensive antibodies to nursing infants, after those women received the initial rounds of COVID-19 vaccines.

This new report looked at the effect on breast milk of the COVID booster shot distributed last year. It tracked outcomes for 14 women who were breastfeeding their newborns.

Antibody levels were tested in each mom's blood (before and after receiving the booster), her breast milk and in each baby's poop.

The study again found that breast milk was transferring COVID-19 antibodies to infants too young to be vaccinated. Having mom get the booster was important since antibody levels can wane over time, the researchers said.

The study was published recently in the journal Frontiers in Medicine.

“When babies are born, they have an immature immune system, so they rely heavily on mom's immune system,”  Joseph Larkin, an associate professor of microbiology and cell science at UF, explained in a university news release. “Breastfeeding can serve as a gap in between while babies are building their own immune system.”

All of this "shows how important breast milk and breastfeeding is for infant health during a pandemic,” Valcarce said.

More information

There's many good reasons to breastfeed; learn more at the American Academy of Pediatrics.

SOURCE: University of Florida, news release, March 5, 2024