SARS-COV-2 enters the host cell through the spinosin (S protein) on the surface of its envelope and binds to the host cell surface-specific viral receptor, angiotensin-converting enzyme 2 (ACE2), so the airway mucosa, oral mucosa, which are in communication with the outside world, and the eyelids and conjunctiva are susceptible to exposure to infection (13, 14). The gene discussed is ACE2; the disease is infection.