inclusion criteria: phase 2 inclusion criteria: age 18 to 90. confirmed covid-19 diagnosis at least one of the following: # respiratory distress, rr ≥ 30 breaths/min without oxygen; # partial arterial oxygen pressure (pao2) / fraction of inspiration o2 (fio2) >100 <300mmhg (1mmhg = 0.133kpa). 4. chest imaging confirms lung involvement and inflammation. 5. inflammatory status as documented by at least one of the following: lactate dehydrogenase (ldh) > normal range, c-reactive protein (crp) ≥ 100mg/l or il-6 ≥ 40pg/ml, serum ferritin ≥ 900ng/ml, xdp >20mcg/ml. phase 3 inclusion criteria: same as above; other criteria tbd based on phase 2 outcomes.

inclusion criteria: phase 2 inclusion criteria: age 18 to 90. confirmed covid-19 diagnosis at least one of the following: # respiratory distress, rr ≥ 30 breaths/min without oxygen; # partial arterial oxygen pressure (pao2) / fraction of inspiration o2 (fio2) >100 <300mmhg (1mmhg = 0.133kpa). 4. chest imaging confirms lung involvement and inflammation. 5. inflammatory status as documented by at least one of the following: lactate dehydrogenase (ldh) > normal range, c-reactive protein (crp) ≥ 100mg/l or il-6 ≥ 40pg/ml, serum ferritin ≥ 900ng/ml, xdp >20mcg/ml. phase 3 inclusion criteria: same as above; other criteria tbd based on phase 2 outcomes.

inclusion criteria: - phase 2 inclusion criteria: 1. age 18 to 90. 2. confirmed covid-19 diagnosis 3. at least one of the following: # respiratory distress, rr ≥ 30 breaths/min without oxygen; # partial arterial oxygen pressure (pao2) / fraction of inspiration o2 (fio2) >100 <300mmhg (1mmhg = 0.133kpa). 4. chest imaging confirms lung involvement and inflammation. 5. inflammatory status as documented by at least one of the following: lactate dehydrogenase (ldh) > normal range, c-reactive protein (crp) ≥ 100mg/l or il-6 ≥ 40pg/ml, serum ferritin ≥ 900ng/ml, xdp >20mcg/ml. - phase 3 inclusion criteria: same as above; other criteria tbd based on phase 2 outcomes.

inclusion criteria: - phase 2 inclusion criteria: 1. age 18 to 90. 2. confirmed covid-19 diagnosis 3. at least one of the following: # respiratory distress, rr ≥ 30 breaths/min without oxygen; # partial arterial oxygen pressure (pao2) / fraction of inspiration o2 (fio2) >100 <300mmhg (1mmhg = 0.133kpa). 4. chest imaging confirms lung involvement and inflammation. 5. inflammatory status as documented by at least one of the following: lactate dehydrogenase (ldh) > normal range, c-reactive protein (crp) ≥ 100mg/l or il-6 ≥ 40pg/ml, serum ferritin ≥ 900ng/ml, xdp >20mcg/ml. - phase 3 inclusion criteria: same as above; other criteria tbd based on phase 2 outcomes.