Women that have been infected and recovered from Covid-19 contain antibodies against the virus in their breast milk, suggests a study published in iScience. The study, which was conducted by the Icahn School of Medicine at Mount Sinai and involved 15 participants, found a robust antibody response within their breast milk that could potentially be leveraged into creating a therapy against Covid-19.
“The SARS-CoV-2 immune response in human milk has not yet been examined, although protecting infants and young children from Covid-19 is critical for limiting community transmission and preventing serious illness and death,” the authors write in the study.
“Overall, these data indicate that a robust sIgA-dominant [a form of antibody commonly found in mucus] SARS-CoV-2 Ab response in human milk after infection should be expected in a significant majority of individuals.”
These results are in line with previous research that found anti-SARS-CoV-2 antibodies in newborn children of previously-infected mothers, and anti-SARS-CoV-2 antibodies in breastmilk of women recently diagnosed with Covid-19 while studying transmission between mother and child. However, the jury is still out on whether any protection granted by the mother’s breastmilk provides immunity to the child against Covid-19.
To decipher whether mothers may be able to pass on protection to their children via breastmilk, the researchers looked at samples from eight people that had recovered from Covid-19 and seven that had suspected Covid-19 3-4 days after their symptoms had alleviated. The samples were then tested to identify whether there were antibodies against SARS-CoV-2 present and the exact type of antibodies they were.
The human body produces many different types of antibodies in the presence of bacteria or viral infection. IgA antibodies act as the first line of defense and are present in the respiratory tract within our mucus to immediately fight any invading pathogen. IgM, on the other hand, is found mainly in the blood and is the first antibody made in response to an infection. IgG take a bit more time to make, but are the most common antibody in the body as they stick around for a long period after infection.
Out of the 15 samples, 80 percent exhibited a strong anti-SARS-CoV-2 IgA response, which is expected as IgA antibodies are the most common antibody passed through breastmilk. Alongside these, 67 percent of the samples also contained IgM and/or IgG antibodies. All antibodies present in the samples directly bound to the Spike protein of SARS-CoV-2, which is necessary for stopping infection.
While promising, the study does have some limitations. The authors note that not all the participants were PCR-tested for Covid-19 and so they cannot be completely certain they were infected, and more research will need to be carried out on a much larger sample size.
The authors are now hoping future research will discover whether these antibodies are capable of providing protection against the virus, and whether extracted breastmilk antibodies could be used as a protective therapy of some kind.