The Spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Arya et al., 2021) is a specialized ligand that mediates viral entry into a cell to initiate infection via the C-terminal domain of the S protein (known as receptor-binding domain, RBD) to attach to the host receptor—angiotensin-converting enzyme 2 (ACE2) (Kuhn et al., 2004; Shang et al., 2020). Here, ACE2 is linked to infection.