1. Aged 18 to 70 years old, inpatients, male or female, 2. Patients with severe novel coronavirus infection: According to the Pneumonitis Diagnosis and Treatment Guideline for the Novel Coronavirus Infection (Trial Version 5) , clinically diagnosed cases (suspected cases with pneumonia imaging features) or suspected cases. Severe patients must also meet any of the following: 1) Respiratory distress, RR>=30 times / minute 2) In the resting state, the oxygen saturation is <=93%, 3) Arterial blood oxygen partial pressure (PaO2) / oxygen concentration (FiO2) <=300 mmHg (1mm Hg = 0.133 kPa). 3. Subjects and / or legal guardians of the subjects volunteered to participate in the study and voluntarily signed informed consent.

1. Aged 18 to 70 years old, inpatients, male or female, 2. Patients with severe novel coronavirus infection: According to the Pneumonitis Diagnosis and Treatment Guideline for the Novel Coronavirus Infection (Trial Version 5) , clinically diagnosed cases (suspected cases with pneumonia imaging features) or suspected cases. Severe patients must also meet any of the following: 1) Respiratory distress, RR>=30 times / minute 2) In the resting state, the oxygen saturation is <=93%, 3) Arterial blood oxygen partial pressure (PaO2) / oxygen concentration (FiO2) <=300 mmHg (1mm Hg = 0.133 kPa). 3. Subjects and / or legal guardians of the subjects volunteered to participate in the study and voluntarily signed informed consent.