Association studies of the 8 HLA genes were carried out by comparing HLA allele frequencies in the 53 sCOVID-19 patients and 423 Japanese healthy controls (Table 1): HLA-A*11:01:01:01 [Pc = 0.013, OR = 2.26 (1.27–3.91)], HLA-C*12:02:02:01 [Pc = 0.043, OR = 2.13 (1.18–3.71)] and HLA-B*52:01:01:02 [Pc = 0.021, OR = 2.22 (1.22–3.87)] were significantly associated with the severity of COVID-19 after multiple corrections. The gene discussed is HLA-C; the disease is COVID-19.