Concentration of SARS-CoV-2 antibodies in COVID-19 recovered women

1. SARS-CoV-2 IgA and IgG antibodies are present in the breastmilk of COVID-19 recovered women

2. Neither presence of symptoms nor time since positive SARS-CoV-2 test were found to be independent predictors affecting antibody concentration in milk

Evidence Rating Level: 2 (Good)

Newborn infants are an at-risk population who are unable to get SARS-CoV-2 vaccines due to their immature immune systems. It is well known that passive immunity can come from maternal milk for the prevention of various diseases, and previous studies have reported human milk as a source of maternal SARS-CoV-2 antibodies. The relative concentrations of these antibodies in milk however, have not been studied. This retrospective cohort study investigated the concentrations of SARS-CoV-2 IgG and IgA in human milk and serum using Enzyme Linked ImmunoSorbent Assay (ELISA) of blood serum and human milk from patients who had recovered from COVID-19 in pregnancy and those who had COVID-19 during time of delivery. Patients had PCR confirmed coronavirus infection during pregnancy or during delivery and lactation. Women with no history of COVID-19 served as controls. All women were discharged home, with no acute symptoms of infection and with n maternal or neonatal deaths due to infection. Maternal blood and breast milk samples were collected. Former virus exposure was highly associated with the prevalence and level of anti- SARS-CoV-2 IgG and IgA antibodies in breastmilk (p <0.001), with concentrations of anti- SARS-CoV-2 IgA antibodies than IgG. No statistically significant difference between antibody levels were seen between symptomatic and asymptomatic women, additionally, no statistically significant correlation was seen between time since positive SARS-CoV-2 test and level of antibody in the timespan studied (up to 229 days). Overall, this study found that SARS-CoV-2 IgA and IgG antibodies are present in human milk in women who had COVID-19 throughout pregnancy or at time of delivery and can last up to 9 months. Future studies can be done to evaluate the protective capacity of human milk against SARS-CoV-2.

Click to read the study in BMC Pregnancy and Childbirth

Image: PD

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