The main difference between a confirmed case of novel coronavirus infection and an asymptomatic infection is whether the patient has clinical symptoms and whether there is any abnormality on chest CT; however, an asymptomatic infection may be converted into a confirmed case. 1. Whether there are clinical symptoms, confirmed cases of novel coronavirus infection usually have clinical symptoms, including fever, cough, fatigue, and other symptoms such as runny nose, sneezing, etc.; asymptomatic infected patients are essentially carriers of the pathogen and do not have the above clinical symptoms. 2. Whether there is any abnormality on chest CT, confirmed cases may have abnormal manifestations on chest CT, including ground glass shadow, patchy exudate shadow, etc.; however, the chest CT of asymptomatic infected patients is completely normal. However, it should be pointed out that some asymptomatic infected patients may develop gradually, and may have fever, cough and other related symptoms, or abnormalities on chest CT, and then they should be confirmed cases of novel coronavirus infection, and no longer be asymptomatic infected patients. Therefore, asymptomatic patients should be isolated and closely monitored for changes in their condition.