Most severely ill patients with novel coronavirus pneumonia develop respiratory distress after one week, and some patients rapidly progress to acute respiratory distress syndrome, septic shock, uncorrectable metabolic acidosis, and bleeding and coagulation dysfunction. The incubation period of novel coronavirus is usually 3-7 days, with a maximum of 14 days, with fever, malaise, and dry cough as the main manifestations. A small number of patients have symptoms such as nasal congestion, runny nose and diarrhea. However, some patients have a low to moderate fever or even no significant fever at the onset. Elderly people and those with chronic underlying diseases are likely to progress rapidly. The specific days of infection with more severe symptoms need to be determined by the patient’s resistance and the amount of virus infected.