Based on epidemiological surveys before January 27, the incubation period of novel pneumonia is generally 3-7 days, with a maximum of 14 days. Initially, fever, malaise and dry cough are the main manifestations. A few patients have symptoms such as nasal congestion, runny nose and diarrhea. Severe cases tend to develop respiratory distress after one week, with rapid progression to acute respiratory distress syndrome, septic shock, uncorrectable metabolic acidosis, and bleeding and coagulation dysfunction in severe cases. It is worth noting that heavy, critically ill patients may have moderate to low fever or even no significant fever during the course of the disease. Some patients present only with low-grade fever and mild malaise, without pneumonia manifestations, and mostly recover after 1 week.