RIPK1 and viral infectious disease: Multiple host proteins have been identified to associate with viral RdRp by means of affinity-purification mass spectrometry (AP-MS).13,14 Recent studies revealed that apart from its polymerase activity, the SARS-CoV-2 nsp12 can hijack host RIPK1 (Receptor-interacting serine/threonine-protein kinase 1)15 and suppress the nuclear translocation of IRF3 (Interferon regulatory factor 3)16 to antagonize host antiviral innate immunity so as to promote viral infection.