Novel coronavirus pneumonia is a serious infectious disease that occurs as a result of infection with a novel coronavirus. There are several main types of clinical manifestations in patients, mild, common, severe and critical. Some patients who are infected with the virus do not show symptoms such as cough, fever and dyspnea of the common type patients, and may only show a cough with a short fever. From being infected to showing mild clinical symptoms until the virus is cleared, there is no special clinical intervention, which is a self-limiting performance process. The process of disease onset without specific treatment of viral conversion is called self-limiting process. A significant proportion of infected cases are observed to be self-limiting process in clinical practice, but are infectious from the time of infection to full recovery; some patients may present as the common type, with clinical fever, cough, and progressive dyspnea; and some patients may present as the heavy and critical type, with a very aggressive clinical course that requires active clinical treatment. Content source: Dr. You Lai