COVID-19 antibodies in breast milk remain 10 months after infection, say researchers

on 29 September 2021

Breastfeeding women who have been infected with COVID-19 continue to have antibodies in their breast milk up to 10 months after infection, according to a study.

Researchers at Mount Sinai Hospital in New York, took breast milk samples from 75 women who had recovered from COVID-19 and found that 88% of the samples had Secretory Immunoglobulin A (IgA) antibodies that blocks infection.

Further investigation found that the women whose breast milk contained IgA antibodies continued to express it for up to 10 months.

Lead Researcher Dr Rebecca Powell said: “This is the breastfeeding population, so knowing if there are antibodies in breast 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.”

The research has now prompted a discussion on whether IgA antibodies extracted from breast milk could benefit adults with severe COVID-19 symptoms: “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,” Dr Powell added.

Dr Powell and her team also investigated coronavirus-specific antibodies in breast milk in 50 women after vaccination with either the Pfizer, Moderna, or Johnson & Johnson (J&J) vaccines. All women injected with Moderna, and 87% who received the Pfizer vaccine had coronavirus-specific IgG antibodies in their milk, with 71% and 51% respectively having virus IgA antibodies. For the J&J vaccine, 38% of women had IgG antibodies and 23% had IgA antibodies in their breast milk.

Dr Powell said: “We know that the level of antibodies produced by RNA vaccines is extremely high compared to other vaccines. You don’t necessarily need that much antibody to protect you from infection, but the milk effect really depends on there being a lot of antibody in your blood that’s transferring into your milk. Because there’s a lower level stimulated by the J&J vaccine, that’s probably why there’s very low levels in milk.”

The research ‘Comparative profiles of SARS-CoV-2 Spike-specific milk antibodies elicited by COVID-19 vaccines currently authorized in the USA’ can be found here.

The research was presented at the Global Breastfeeding and Lactation Symposium on Tuesday 21 September 2021.

Source: The Guardian