The second model was K18-hACE2 transgenic mice,for which SARS-CoV-2infection can cause severe lung inflammation and death.37,38 After infection, the mice were orally administered with WU-04 (100,200, or 300 mpk, twice daily), PF-07321332 (300 mpk, twice daily),or the vehicle control (Figure 6a). This evidence concerns the gene KRT18 and infection.