Novel coronavirus infection mainly causes viral pneumonia, with dry cough, malaise and fever as common symptoms, while nasal congestion, diarrhea and runny nose can be seen in a small number of patients. Severe cases tend to develop respiratory distress after a week, and severe cases can progress rapidly and even lead to death. The official criteria for recovery and discharge from the hospital are a return to normal temperature for more than 3 days, significant improvement in respiratory symptoms, and two consecutive negative nucleic acid tests for respiratory pathogens (at least 1 day between samples).