For the PB control group, inoculation of K18-hACE2 mice with a 50% tissue culture infective dose (TCID50)/mouse SARS-CoV-2 of 25 (based on doses leading to 100% mouse death in our preliminary study) resulted in 100% mortality, lung disease with signs of interstitial pneumonia, immune infiltration, and extensive spread of the virus to the central nervous system and the brain (Fig. 5 and 6; Fig. S4). This evidence concerns the gene KRT18 and lung disorder.