The K18-hACE2 mice have previously been shown to develop severe lung lesions following intranasal infection with SARS-CoV-2, including acute pneumonia, alveolar collapse, interstitial as well as perivascular and vascular immune cell infiltration, alveolar septal thickening, and proteinaceous debris in alveolar spaces [12,14,61,62,63,64]. Here, KRT18 is linked to pneumonia.