Controversy remains regarding how useful the K18-hACE2 mouse models is for understanding human disease, although a considerable body of literature argues that many aspects of respiratory COVID-19 are recapitulated in this model (Yinda et al., 2021; Zheng et al., 2021; Bishop et al., 2022; Park et al., 2022; Ye et al., 2023). This evidence concerns the gene KRT18 and COVID-19.