The S1 subunit is responsible for binding to the host cell receptor, and the S2 subunit assists with viral and host cell fusion.1 While the MERS-CoV S GP binds to DPP-4 (dipeptidyl peptidase 4) expressed on epithelial tissue, both SARS-CoV-2 and SARS-CoV bind to human cells via the ACE-2 (angiotensin-converting enzyme 2) receptor.5 In addition to having different amino acid residues within the RBD (receptor-binding domain) of the S protein compared to SARS-CoV, another novel structural feature of SARS-CoV-2, is the presence of a polybasic furin cleavage site, at the junction of S1 and S2.