The lack of ISGF-3 activation in response to both type I and type III IFNs, an immunological phenotype even more severe than that of patients with AR IRF7 deficiency, whose cells produce IFN-β but do not amplify either type I or type III IFNs (19), further suggested that this patient might even develop a fulminant form of COVID-19 (19, 28). Here, IRF9 is linked to COVID-19.