The emergence of asymptomatic infected individuals is a manifestation of the body’s defense function being in a state of hold with the virus. After the pathogen enters the human body through various ways, according to the strength of the body’s defense function and the number of pathogens and virulence, the infection process can appear five different endings, namely, the pathogen is cleared, hidden infection, dominant infection, the pathogen carries the state and latent infection. Asymptomatic infected persons are pathogen carriers, which means that pathogens do not show any disease state after invading the human body, but are able to carry and eliminate pathogens and become the source of infectious disease epidemics. Asymptomatic infected people and people’s individual immune differences, when the human body resistance is strong, the body’s defense function and the virus is in a state of hold, it is only manifested as carrying the virus and no clinical symptoms. However, when the body’s resistance drops, people will show the corresponding clinical manifestations. In the case of C.N.C.P., for example, asymptomatic C.N.C.P. patients do not develop clinical symptoms such as fever, nasal congestion, runny nose, dry cough, sore throat, and fatigue. Often the results are positive only when a nucleic acid test is done. Asymptomatic infected people are more infectious, because there is no relevant clinical symptoms, so it is relatively hidden, which will bring a certain degree of difficulty to the prevention and control. Tip: “New coronavirus pneumonia and new coronavirus pneumonia” mentioned in this article have been renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.