SERINC5 and infection: Major functions ascribed to SARS-CoV-2 ORF7a during infection include impairing the antiviral effect of host factors, including serine incorporator 5 (SERINC5) [13] and bone marrow stromal antigen 2 (BST2)/tetherin [14], inhibiting the type I interferon (IFN-I) response [15,16], and downregulating the levels of major histocompatibility complex I (MHC-I) [17,18] on the cell surface.