In that study, breastfeeding mothers who manifested symptoms of SARS-CoV-2 infection during pregnancy produced colostrum with a higher proportion of the two NK cell subtypes, CD3−CD56dimCD16+CD27− and CD3−CD56brightCD16−CD27+IFN−γ+, associated with a lower concentration of the cytokines IFN-α2 and GM-CSF, when compared to the colostrum of breastfeeding mothers asymptomatic for the infection. The gene discussed is IFNA2; the disease is infection.