IFNA1 and viral pneumonia: Among the various adverse effects of GC, the suppression of antiviral immunity is particularly troublesome to viral pneumonias such as COVID-19, which may explain the potentially harmful effect of DEX in non-severe COVID-19.9 In this study, we analyzed a cohort of moderate to severe COVID-19 patients with high prevalence of GC and IFN exposures and identified an IFN–GC synergy that reduced GC-mediated suppression of antiviral immunity which adversely affected COVID-19 recovery.