In our cohort, we have previously reported heterologous immunity suggestive of a similar back-boost effect directed against the spike protein in severe COVID-19, with strong correlations of anti-spike IgG against SARS-CoV-2 and eCoVs of the genus Betacoronavirus (OC43 and HKU1) in severely ill patients [11]. The gene discussed is CHMP5; the disease is COVID-19.