KRT18 and infection: Consistent with the reported resistance to IFN-I signaling in vitro (Guo et al., 2021Preprint; Thorne et al., 2021Preprint), SLR14 treatment was less effective against infection with B.1.351 or B.1.1.7 in vivo, conferring ∼40–50% net protection in K18-hACE2 mice (60% survival in SLR14-treated mice compared with 10–20% survival in vehicle controls; Fig. 6, J–M; Fig. S4, E and F).