Clinical improvement time of 28 days after randomization;The 7-point scale;7 points: death;6 points: admission to ECMO and / or mechanical ventilation;5 points: Hospitalized for non-invasive ventilation and / or high-flow oxygen therapy;4 points: hospitalization for oxygen therapy;3 points: Hospitalization does not require oxygen therapy;2 points: discharged but not restored to normal functional status;1 point: discharged to normal function;

Clinical improvement time of 28 days after randomization;The 7-point scale;7 points: death;6 points: admission to ECMO and / or mechanical ventilation;5 points: Hospitalized for non-invasive ventilation and / or high-flow oxygen therapy;4 points: hospitalization for oxygen therapy;3 points: Hospitalization does not require oxygen therapy;2 points: discharged but not restored to normal functional status;1 point: discharged to normal function;