In the first nine months of the pandemic, about 116 million babies were born worldwide, according to Unicef estimates. This left researchers to answer a critical question: Could the virus be transmitted through breast milk? Some assumed it could. However, when several groups of researchers tested the milk, they found no trace of the virus, only antibodies – suggesting that drinking the 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 similarly transferred to babies. None of the vaccine trials included pregnant or breastfeeding women, so researchers had to find breastfeeding women who qualified for the first rollout of the vaccine.
“There’s reason to be excited,” he said Dr. Kathryn Gray, a fetal medicine specialist at Brigham and Women’s Hospital in Boston, who has conducted similar studies. “We suspect it may provide some level of protection.”
But how do we know for sure? One way to test this – exposing these babies to the virus – is of course unethical. Instead, some researchers have tried to answer the question by studying the properties of the antibodies. Do they neutralize, which means 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 capacity to prevent the spread of the virus and block the ability of the virus to infect host cells that will result in disease,” Yariv Wine, an applied immunologist at Tel Aviv University, wrote in an email.
Research is too early for vaccinated mothers who are breastfeeding to act as if their babies cannot be infected, says Dr. Kirsi Jarvinen-Seppo, Head of Pediatric Allergy and Immunology at the University of Rochester Medical Center. Dr. Jarvinen-Seppo has conducted similar studies. “There is no direct evidence that the Covid antibodies in breast milk protect the infant – only evidence to suggest that this may be the case,” she said.