Although the antigenicity of this peptide in SARS-CoV-2 remains to be experimentally determined, and currently, most vaccine designs are focusing on the RBD of the S1 subunit, we speculate that a vaccine based on this epitope-rich region (786Q–828A) in the S2 subunit of the SARS-CoV S protein may also elicit broad NAbs that can cross-react with other virus members among this coronavirus family to provide broader protections (i.e., against simultaneous infections of both SARS-CoV and SARS-CoV-2). The gene discussed is PROS1; the disease is infection.