Study: Coronavirus antibodies found in breast milk 10 months after COVID-19 infection

A new study suggests that breastfeeding women who have had COVID-19 secrete neutralizing antibodies in their milk for up to 10 months, offering their babies protection and potentially helping those with a serious case of the virus.

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The study, which was headed by Dr. Rebecca Powell at Mount Sinai Hospital in New York, looked at whether the antibodies produced by the women and present in their breast milk could neutralize the virus and how long those antibodies were produced following a bout with COVID-19.

“This is the breastfeeding population, so knowing if there are antibodies in the milk, how long they’ll be protective after being infected, or which vaccine is going to give your baby the best antibody protection, is very important information, and will be relevant for a long time to come,” Powell told The Guardian.

The study looked at breast milk samples from 75 women who had the COVID-19 virus and were considered recovered.

The study found that 88% of the samples contained IgA antibodies. The main antibody in breast milk is called a secretory immunoglobulin, or IgA for short. Those antibodies stick to the lining of a baby’s respiratory and intestinal tract to offer protection from disease.

Powell’s research showed that the IgA antibodies in the breast milk tested were, in most cases, able to neutralize the novel coronavirus. To neutralize the virus means it is blocked from infecting the body’s cells.

According to verywell.com, the IgA antibodies can protect a baby “from a variety of illnesses including those caused by bacteria, viruses, fungi, and parasites.”

Those antibodies are different from the antibodies produced when a person is given a vaccine. Those antibodies are called immunoglobin G, or IgG antibodies. According to kidshealth.org, IgG is in “blood and other body fluids, and protects against bacterial and viral infections. IgG can take time to form after an infection or immunization.”

Powell presented the results of the study to the Global Breastfeeding and Lactation Symposium last month. She also pointed out that the antibodies in breast milk could also be beneficial to others who are severely ill with the virus.

“It could be an incredible therapy, because Secretory IgA is meant to be in these mucosal areas, such as the lining of the respiratory tract, and it survives and functions very well there,” Powell said.

“You could imagine if it was used in a nebulizer-type treatment, it might be very effective during that window where the person has gotten quite sick, but they’re not yet at the point of being admitted to intensive care.”

The study also looked at the antibody levels in breast milk in 50 women after vaccination with either the Pfizer, Moderna, or Johnson & Johnson shots.

Of the 50 women tested, all those who received the Moderna vaccine, and 87% of those who received the Pfizer vaccine, had coronavirus-specific IgG antibodies in their milk.

Seventy-one percent of those who received the Moderna vaccine and 51% of those who had the Pfizer shot had virus-specific IgA antibodies in their breast milk.

For those who received the Johnson & Johnson vaccine, 38% had IgG antibodies and 23% had IgA antibodies against coronavirus in their milk.