inclusion criteria: 1. males and non-pregnant females who are 18 years or older (inclusive). 2. signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. 3. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) 4. hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）\<300 mmhg.

inclusion criteria: 1. males and non-pregnant females who are 18 years or older (inclusive). 2. signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. 3. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) 4. hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）\<300 mmhg.

inclusion criteria: males and non-pregnant females who are 18 years or older (inclusive). signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）<300 mmhg.

inclusion criteria: males and non-pregnant females who are 18 years or older (inclusive). signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）<300 mmhg.

inclusion criteria: 1. males and non-pregnant females who are 18 years or older (inclusive). 2. signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. 3. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) 4. hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）<300 mmhg.

inclusion criteria: 1. males and non-pregnant females who are 18 years or older (inclusive). 2. signed informed consent. subjects are to provide informed consent prior to any study procedures being performed. consent can be oral if a written consent cannot be expressed. where it is not practicable to approach a subject highly dependent on medical care, or the subject is not capable of making such a decision, consent will be sought from the legal representative of the subject. subjects enrolled in the study based on consent by the legal representative will be given the opportunity to provide written confirmatory consent when and if they become able to do so. if the subject declines to confirm consent, they will be withdrawn from the study at the point where they decline consent. 3. virological diagnosis of severe acute respiratory syndrome coronavirus 2（sars-cov-2）infection (documentation of real-time polymerase chain reaction（pcr）or equivalent within the last 72h positive results is available before screening) 4. hospitalized due to clinical/chest image diagnosis of sever pneumonia. severe pneumonia defined as dyspnea, hemoglobin oxygen saturation（spo2）on room air at rest ≤93% or partial pressure of oxygen（pao2）/fraction of inspired oxygen（fio2）<300 mmhg.