Our study revealed that the increased susceptibility to infection as measured by weight loss through day 6 p.i. in Ifnlr1–/– compared with WT animals could not be attributed solely to differences in the induction of canonical innate immune responses to the virus and virus titers since expression of ISGs, IFN, inflammatory genes, and SARS-CoV-2 titer was only transiently increased in the absence of IFN-λ signaling. This evidence concerns the gene IFNA1 and infection.