Coronavirus has an envelope, the particles are round or oval, often pleomorphic, with a diameter of 50–200 nm [18]. S protein is located on the surface of the virus and forms a rod-shaped structure. As one of the main antigenic proteins of the virus, the S protein gene is the main target used for typing [19]. Xu et al. also reported that SARS-CoV-2 S-protein supports a strong interaction with human angiotensin-converting enzyme 2 (ACE2) molecules, which means that the virus poses a significant public health risk for human transmission by the S-protein–ACE2 binding pathway [18].