The results of the present study showed that the gene expression of IFNRI, IFNRII, and IRF9 was significantly upregulated in the peripheral blood cells of patients with COVID-19 in all four age groups under 20 years, 20 to 40 years, 40 to 60 years, and over 60 years compared to aged-matched control groups. Here, IRF9 is linked to COVID-19.