inclusion criteria: 1. male and female \>18 and \<85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with mild to moderate ards: 1. 100\< pao2/fio2 ≤300; based on the berlin definition of ards 2. 148\< spo2/fio2 ≤315; based on the kigali modification for ards * if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: 1. male and female \>18 and \<85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with mild to moderate ards: 1. 100\< pao2/fio2 ≤300; based on the berlin definition of ards 2. 148\< spo2/fio2 ≤315; based on the kigali modification for ards * if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: male and female >18 and <85 years of age. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. patient with mild to moderate ards: 100< pao2/fio2 ≤300; based on the berlin definition of ards 148< spo2/fio2 ≤315; based on the kigali modification for ards if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. signed written informed consent by the patient. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: male and female >18 and <85 years of age. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. patient with mild to moderate ards: 100< pao2/fio2 ≤300; based on the berlin definition of ards 148< spo2/fio2 ≤315; based on the kigali modification for ards if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. signed written informed consent by the patient. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: 1. male and female >18 and <85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with mild to moderate ards: 1. 100< pao2/fio2 ≤300; based on the berlin definition of ards 2. 148< spo2/fio2 ≤315; based on the kigali modification for ards - if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: 1. male and female >18 and <85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with mild to moderate ards: 1. 100< pao2/fio2 ≤300; based on the berlin definition of ards 2. 148< spo2/fio2 ≤315; based on the kigali modification for ards - if available, pao2 will be obtained, otherwise, spo2 will be used for ards assessment. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: 1. male and female >18 and <85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with pao2/fio2 ≤300 mmhg and >100 mmhg (equivalent to sao2/fio2 ≤315 mmhg and >235 mmhg) corresponding to mild to moderate ards. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.

inclusion criteria: 1. male and female >18 and <85 years of age. 2. laboratory confirmation of sars-cov-2 infection by rt-pcr from any diagnostic sampling source. 3. patient hospitalized due to covid-19 within 7 days prior to enrollment, meeting the criteria for severe or critical covid-19 as follows: 1. severe covid-19 - defined as shortness of breath at rest, or respiratory distress, or rr ≥30 per minute, or spo2≤93% on room air at sea level. 2. critical covid-19 - defined as respiratory failure, requiring at least one of the following: oxygen delivered by high-flow nasal cannula or noninvasive positive pressure ventilation. 4. patient with pao2/fio2 ≤300 mmhg and >100 mmhg (equivalent to sao2/fio2 ≤315 mmhg and >235 mmhg) corresponding to mild to moderate ards. 5. signed written informed consent by the patient. 6. women and men who are of childbearing potential, willing to use acceptable contraceptive measures during 4 weeks from enrollment.