Breast milk can protect babies against Covid – 01/19/2023 – Equilibrium and Health

A study led by researchers at the University of Florida offers new evidence that breast milk from mothers immunized against Covid-19 can protect babies. Currently, there are no approved vaccines for children under six months of age and nutrition can be a way to provide immunity.

The research, published last week in the scientific journal Journal of Perinatology, complements the evidence presented in 2021, when scientists disclosed that the breast milk of immunized women contains antibodies against Sars-CoV-2, the virus that causes Covid-19.

“Our hypothesis was that we would find specific antibodies for Sars-CoV-2 in children breastfed by vaccinated women, an idea based on previous studies that showed that maternal antibodies against certain enteric pathogens can be detected in the stool of infants”, says Joseph Larkin, senior author of the research and professor at the University of Florida.

In the new study, scientists analyzed the babies’ feces and also found antibodies to the new coronavirus, indicating that these proteins are passed through breastfeeding and manage to reach the children’s gastrointestinal tract.

For the analysis, they relied on blood and milk samples from 34 mothers immunized with Pfizer or Moderna vaccines, as well as stool samples from 24 babies. The material was collected at different times, which made it possible to compare antibody levels over time.

In all, 96 samples of maternal blood, 101 of milk and 31 of feces collected before vaccination, from 15 to 30 days after the first dose, and after seven days to six months after the second dose (not all participants contributed material at various times).

In the next step, the researchers carried out tests in vitro to verify whether the antibodies found in the samples were capable of neutralizing a pseudovirus that mimics Sars-CoV-2 and the results were positive.

The group found that the levels of antibodies of the types IgA and, mainly, IgG (associated with the immune response of memory) in the feces of the infants after the mothers’ vaccination were higher than the control parameters.

It also verified a 50% increase in the neutralization capacity in breast milk samples collected six months after vaccination, when there is already a reduction in antibody levels.

With the results, they raise in the article the idea that IgA and IgG antibodies against Sars-CoV-2 secreted in breast milk can offer protection to babies and potentially reduce the severity of symptoms related to infection by the coronavirus.

The study, however, has limitations, starting with the small number of participants. Larkin explains that, with the advancement of vaccination, it became more difficult to recruit women before the immunizer was administered, which is why the limited group.

Another restriction is the fact that the possibility of mothers or babies being infected by Sars-CoV-2 and not diagnosed was not considered.

In addition, many of the participating babies were older than six months and were also eating other foods. “In combination with the small sample, this may have interfered with the concentration of antibodies in the feces and the results on the ability to neutralize, since children fed exclusively with breast milk may have a higher level of antibodies”, say the scientists in the text.

Still, they reckon that together, the two studies offer a more complete picture of how vaccination against Covid-19 during pregnancy and breastfeeding can protect mother and child. Larkin even hopes that the results will encourage breastfeeding and encourage more research. “Now we’re interested in better understanding how antibodies and other elements in breast milk help protect babies.”