The virus has:

• A diameter ranging from 60 to 140 nm
• An envelope with protein spikes
• A single-stranded positive sense RNA genome (that is ∼30,000 nucleotides in length) which encodes 27 proteins including an RNA-dependent RNA polymerase (RdRP). RdRP acts in conjunction with nonstructural proteins to maintain genome fidelity.
• Four structural proteins: spike surface glycoprotein (S), small envelope protein (E), matrix protein (M), and nucleocapsid protein (N). *The S gene codes for the receptor-binding spike protein that enables the virus to infect cells. This spike protein mediates receptor binding and membrane fusion, which determines host tropism and transmission capabilities.