Initially, we monitored antibody-mediated protection against COVID-19 or quadrivalent flu vaccines by measuring the levels of binding IgG recognizing anti-SARS-CoV-2 trimeric S protein (Figure 2A) and specific anti-flu antibodies (measured as HAI titers) against all the vaccine antigen components (here called A/Wisconsin, A/Cambodia, B/Phuket and B/Washington) (Figure 2B–E). The gene discussed is PROS1; the disease is COVID-19.