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