CA2 and COVID-19: Here, we selected five significant proteins for COVID-19 non-severe versus severe comparison: heparin cofactor 2 (SERPIND1), thyroxine-binding globulin (SERPINA7), angiotensinogen (AGT), carbonic anhydrase-1 (CA1), and carbonic anhydrase-2 (CA2) (Supplementary Table 9) for docking study.