A new study from the University of Florida provides more evidence that the breast milk of people vaccinated against COVID-19 provides protection to infants too young to receive the vaccine.
This latest study follows up on findings published in 2021 showing that the breast milk of vaccinated people contained antibodies against SARS-CoV-2, the virus that causes COVID-19. The new study, published in the Journal of Perinatology, analyzed the stool of infants that consumed this breast milk and found SARS-CoV-2 antibodies there as well.
Using a technique called a neutralization assay, the researchers showed that the antibodies found in the infants’ stool offered protection against the virus. The assay begins by isolating antibodies from the stool and adding them to a special line of cells that have the kind of receptors the SARS-CoV-2 virus uses to enter the cell. The researchers then introduce a SARS-CoV-2 pseudovirus, which acts like the virus that causes COVID-19 but is safer to use in the lab. The pseudovirus is fluorescent, so when it binds to a cell, the cell lights up.
While the virus that causes COVID-19 is often thought of as mainly affecting the lungs, it can also invade the gut, which is why finding antibodies there is significant, the researchers said.
The antibodies ingested through breast milk may provide a protective coating in the infants’ mouths and gastrointestinal tract.
Dr. Vivian Valcarce Luaces, the study’s other first author and a postdoctoral fellowship trainee in neonatology
The study also measured and tested antibodies found in the mothers’ blood plasma and breast milk soon after vaccination and then again about six months later. The researchers found that the antibodies in the plasma and milk of vaccinated people were better able to neutralize the virus, though they also observed that antibody levels decreased at the six-month mark, which other vaccine studies have found as well.
Dr. Josef Neu, one of the study’s co-authors and a professor in the UF College of Medicine department of pediatrics, division of neonatology, said the first and second studies together give a more complete picture of how vaccinating against COVID-19 during pregnancy and breastfeeding may be protective for parent and child.
The researchers say larger studies are needed to answer that question, as this latest study included 37 mothers and 25 infants, a relatively small number of participants.
However, this study adds to a growing body of research revealing how vaccination against COVID-19 during pregnancy and breastfeeding may protect newborns, the researchers say. Currently children under sixth months of age cannot receive the vaccine, so breast milk may be the only avenue for providing immunity.
The study was funded by grants from the Children’s Miracle Network and The Gerber Foundation. (PS/newswise)
