In contrast to early omicron variants (Meng et al., 2022; Zhao et al., 2022; Qu et al., 2023), original ancestral isolates show a preference for TMPRSS2 utilization, and rapid fulminant infection of K18-hACE2 brains by such viruses is well described (Rothan et al., 2022; Seehusen et al., 2022). This evidence concerns the gene TMPRSS2 and infection.