New research indicates human milk may contain antibodies to protect against future COVID-19 infection

September 2, 2022 - Human milk is known for its protective benefits, especially for preterm and immunocompromised infants who are at higher risk for necrotizing enterocolitis (NEC), sepsis, and mortality. Now human milk has a new benefit: Protection against COVID-19 diseases.


A new study published in the Journal of Perinatology discovered human milk appears to carry and deliver protective antibodies reactive to SARS-CoV-2.


The study design compared two groups of human milk samples. Group one contained 41 human milk samples collected from women during the 2020 COVID-19 pandemic. Group two contained 16 human milk samples collected two years prior to the novel coronavirus outbreak.


Two significant findings emerged.


The first revealed 2020 human milk samples from women who experienced viral respiratory infection had 3.5 times higher S1 + S2-reactive IgG antibodies in their breast milk than women who did not experience symptoms in the past year.


The second showed S1 + S2-reactive IgG antibodies from 2020 human milk samples were higher than 2018 breast milk samples collected two years prior to the COVID-19 pandemic.


Production of these S1 + S2-reactive IgG antibodies in human milk is a possible protection against future COVID-19 infection in infants. In essence, the presence and volume of these antibodies could very well “provide a passive herd immunity to breastfed infants and protect them against COVID-19 diseases.”


The higher antibodies count in the 2020 human milk sample group indicate this passive herd immunity to breastfed infants may already be happening.


Such human milk antibodies could be useful to protect against and neutralize future coronavirus pandemics. Such protection would be invaluable for vulnerable populations.


Lead researcher Dr. Veronique Demers-Mathieu, PhD, explains, “SIgA and SIgM reactive to SARS-CoV-2 S1+S2 and nucleocapsid did not differ between 2020 and 2018 human milk groups due to their cross-reactive and polyreactive properties. Human milk secretory antibodies possess several advantages compared to convalescent plasma antibodies (IgG/IgM) to protect against COVID-19 as they have a higher capacity to neutralize various pathogens (including SARS-CoV-2).” Medolac Laboratories invites mothers who had a confirmed COVID-19 diagnostic to contact Dr.  Demers ( to participate in her next study. 


These findings are significant to breastfeeding mothers, who may find comfort in the additional protection their breast milk provides, and to researchers, who continue to identify ways to reduce COVID-19 disease outbreak and impact.