Primary Outcomes
Description: Removal of all oxygen support (with stable SpO2)
Measure: Percent of subjects who Return to Room Air (RTRA) (main study)
Time: by Day 28
Measure: Percent of subjects with improved COVID-19 Clinical Status Scale (sub-study)
Time: Day 14
Secondary Outcomes
Measure: All-cause mortality rate (main study) Time: at Day 28
Measure: Percent of subjects who Return to Room Air (RTRA) (main study) Time: by Day 21
Measure: Time (in days) to RTRA (main study) Time: Days 10, 14, 21, 28
Measure: Percent of subjects who achieve clinical stability (main study) Time: by Day 28
Measure: Percent of subjects discharged (without mortality and hospice) (main study) Time: by Days 14, 21, 28 and 35
Measure: Time (in days) to first hospital discharge (without hospice) (main study) Time: through Day 35
Measure: Total number of inpatient days (main study) Time: up to Day 35
Measure: Baseline SAD-RV infection-related mortality rate (main study) Time: at Day 28
Measure: Baseline SAD-RV infection-related mortality rate (main study) Time: at Day 35
Measure: All-cause mortality rate (main study) Time: at Day 35
Measure: Change in pulmonary function (FEV1% predicted) (main study) Time: Day 1, Day 7, Day 14, Day 28
Measure: Time to improved COVID19 clinical status (Sub-study) Time: Day 5, Day 10, Day 21, Day 28
Measure: Time to RTRA Time: Day 10, Day 14, Day 21, Day 28
Measure: Time to Clinical stability Time: Day 14, Day 21, Day 28
Measure: Time to SARS-CoV-2 RNA in the respiratory specimens being undetectable Time: Day 5, Day 10, Day 14, Day 21, Day 28
Measure: Time to Clinical deterioration Time: Day 5, Day 10, Day 14, Day 21, Day 28
Measure: Time to Discharge from hospital (without readmission before Day 28). Time: Day 14, Day 21, Day 28
Measure: Time to Death (all causes) Time: Day 14, Day 21, Day 28