Sequentially, as it has been demonstrated that S protein in SARS and COVID-19 reveals 77.5% similarity in amino acid sequences, an IgG human anti-SARS molecule called 47D11 antibody (47D11Ab) can bind to S-protein-expressing cells (S1b-RBD) with an acceptable affinity and can simultaneously prevent VEROE6 cells from being infected with SARS and COVID-19 viruses. The gene discussed is PROS1; the disease is COVID-19.