The K18-hACE2 transgenic (K18-hACE2) mouse, where hACE2 expression is driven by the epithelial cell cytokeratin-18 (K18) promoter, developed to study the pathogenesis of SARS-CoV infection [41], is frequently employed to address a broad range of questions regarding SARS-CoV-2, as the expression of hACE2 appears to convey higher binding affinity than its murine counterpart. This evidence concerns the gene KRT18 and severe acute respiratory syndrome.