Through differential gene screening, Zhang et al.399 identified mutations in type-I IFN genes among severe COVID-19 patients, and they found that at least 3.5% of patients with severe COVID-19 had genetic defects in genes associated with TLR3- and regulatory factor 7 (IRF7)-dependent induction and amplification of type-I IFN. This evidence concerns the gene TLR3 and COVID-19.