Depending on the degree of the disease, the symptoms exhibited are different: 1. Asymptomatic virus carriers do not show obvious symptoms after infection, only the virus is detected through the respiratory tract, so many areas now require people returning from infected areas to take the initiative to report and quarantine. 2. Mild patients have only fever, cough, chills and physical discomfort. 3. Early stage of severe patients, especially the first 3-5 days mainly manifest as fever, cough, and gradually increasing fatigue. 1 week later, the disease gradually worsens and develops into pneumonia or even severe pneumonia, and severe patients may have accelerated breathing, respiratory failure, and multi-organ damage.4. If the disease further worsens it may require a ventilator to sustain life, which may lead to death. There is a gradual aggravation of the disease, which is often most severe by the 2nd week.