These results are consistent with the recent report by Anderson et al that prepandemic samples with detectable cross-reactive SARS-CoV-2 antibodies had higher anti-OC43 S protein antibody levels, and SARS-CoV-2 infection boosted antibody levels to HCoV-OC43 but not HCoV-NL63 among COVID-19 patients [23]. The gene discussed is PROS1; the disease is COVID-19.