KRT18 and COVID-19: The K18-hACE2 transgenic mice are highly susceptible to SARS-CoV-2 infection and accurately mimic COVID-19 symptoms in humans upon intranasal infection, including body weight loss, rapid breathing, fever, and inactivity [32] The infected mice typically reach criteria for euthanasia within 5–8 days post-infection when infected with SARS-CoV-2 at 1 × 105 PFU [55].