Argentine researchers have conducted studies that would prove that women vaccinated with Sinopharm, AstraZeneca, and Sputnik V would pass on immunity against COVID-19 to their children through breast milk.
Scientists at the Leloir Institute Foundation (FIL) said their findings were the first scientific evidence on the response in breastfeeding mothers to these types of immunizers, which is of key importance since there are no inoculants available for babies under 6 months of age.
The work evaluated the levels of IgG and IgA anti-SARS-CoV-2 antibodies in serum and milk samples from 208 breastfeeding women with or without previous SARS-CoV-2 infection.
Diego Ojeda, one of the scientists behind the investigation said that ”until now, only passive immunity transfer had been studied in mothers vaccinated with messenger RNA platforms (Pfizer and Moderna) and there was no scientific evidence confirming the transfer of antibodies with viral or inactivated vector platforms widely used in Argentina, such as the AstraZeneca, Sputnik V, and Sinopharm vaccines. This was what we did.
The study showed that the vaccines available in Argentina generate a humoral immune response that produces IgG and IgA antibodies, Ojeda added.
Another finding was that the IgA antibody response to the vaccines was similar in both milk and plasma, regardless of the platform received, he also pointed out.
The IgA antibodies that are secreted from the mammary glands have the capacity to neutralize the pathogens to which lactating mothers have been exposed or immunized through vaccines. Our study was to detect and quantify these SARS-COV-2 specific IgA antibodies in breast milk,” Ojeda elaborated.
The study was undertaken with help from the Human Milk Bank at the public Ramón Sardá Hospital in Buenos Aires, which in February 2021, when breastfeeding mothers were included in the vaccination campaign against COVID-19, began enrolling volunteers from its donor registry. Some of the women had already had SARS-CoV-2 infection and were grouped as convalescents, while those who had not become ill were part of the control group.
The mothers participating in the study were instructed on how to collect the milk samples at home and then delivered them to the University of Buenos Aires School of Medicine, where they also underwent blood tests.