IFNB1 and infection: Since infection with β-coronaviruses induced delayed IFN responses (Figs. 1B–1D), and because we wanted to mimic the increased IFN responses observed in CI patients with COVID-19 (Fig. 1A), we treated MHV-infected or SARS-CoV-2–infected wild type (WT) mice with recombinant IFN-β and examined the pathology and lethality.