OAS1 and infection: It is understood from other pathogens that innate defences determine the outcome of the infection, the pathogenesis, and the host range; influenza A virus is restricted by interferon-inducible transmembrane (IFITM) proteins [57], and 2′-5′-oligoadenylate synthetase 1 (OAS1) binds to dsRNA structures in the SARS-CoV-2 5′-UTR and blocks SARS-CoV-2 replication [58].