In the first nine months of the pandemic, around 116 million babies were born around the world, according to Unicef estimates. This left researchers scrambling to answer a crucial question: Could the virus be transmitted through breast milk? Some people assumed it was possible. But as several groups of researchers tested the milk, they found no trace of viruses, only antibodies – suggesting that drinking milk could protect babies from infection.
The next big question for breast milk researchers was whether the protective benefits of a Covid vaccine could be passed on to babies in the same way. None of the vaccine trials included pregnant or breastfeeding women, so researchers had to find qualified breastfeeding women for the first deployment of the vaccine.
Through a Facebook group, Rebecca Powell, breastmilk immunologist at Icahn School of Medicine in Mount Sinai in Manhattan, found hundreds of doctors and nurses willing to share their breastmilk periodically. In her most recent study, which has not been officially published, she analyzed the milk of six women who received the Pfizer-BioNTech vaccine and four who received the Moderna vaccine, 14 days after the women received their vaccine. second injection. She found a significant number of a particular antibody, called IgG, in each of them. Other researchers have had similar results.
“There are reasons to be excited,” said Dr. Kathryn Gray, a specialist in maternal fetal medicine at Brigham and Women’s Hospital in Boston, who has conducted similar studies. “We’ll assume that might provide some level of protection.”
But how do we know for sure? One way to test for this – to expose these babies to the virus – is, of course, unethical. Instead, some researchers have attempted to answer the question by studying the properties of antibodies. Are they neutralizing, that is, they prevent the virus from infecting human cells?
In a draft of a small study, an Israeli researcher found that they were. “Breast milk has the ability to prevent viral spread and block the ability of the virus to infect host cells that will lead to disease,” Yariv Wine, an applied immunologist at Tel Aviv University, wrote in an email. .
The research is too premature for vaccinated breastfeeding mothers to act as if their babies cannot be infected, however, said Dr Kirsi Jarvinen-Seppo, head of the pediatric allergy and immunology department at the Pediatric Allergy and Immunology Department. University of Rochester, which has been conducting similar studies. “There is no direct evidence that Covid antibodies in breast milk protect the infant – only evidence to suggest that this could be the case,” she said.