These antibodies were linked to preexisting S-protein-specific cross-reactive memory B cells to human CoVs that might have been activated after SARS-CoV-2 infection.30 Also, infection with endemic human CoVs was shown to produce little cross-reactivity to SARS-CoV and MERS-CoV where patients with SARS were reported to have increased levels of anti–HCoV-229E, anti–HCoV-NL63, and anti–HCoV-OC43 antibodies in paired acute/convalescent samples.31 The gene discussed is PROS1; the disease is infection.