Anti- SARS-CoV-2 RBD-S1 IgG in all milk samples of vaccinated mothers. The mean IgG level was 12.19 ± 11.74 BAUs per mL (95% CI: 9.77–14.60; p <.001). The mean IgG levels were significantly higher than the levels from the control group (no vaccination, no previous infection) (0.02 ± 0.05 BAUs per mL [95% CI: 0.01–0.05; p<0.001]). The gene discussed is PSMD1; the disease is infection.