Initially, the K18‐hACE2 mouse model was so severe that mice reached the humane endpoint by around 6 days post infection (d.p.i.).[20, 21] Even lower infection doses, such as 2 × 104 and 2 × 103 PFU or 103 TCID50 SARS‐CoV‐2, resulted in 40%–50% of mice reaching the humane endpoint by 7–11 d.p.i. [22, 23, 24]. The gene discussed is KRT18; the disease is infection.