inclusion criteria: * age 18-85 years, * admitted to the hospital because of confirmed positive sars-cov-2 (covid-19 infection). * evidence of pulmonary involvement on ct scan or x-ray of the chest, * symptom onset within the previous 10 days and at least one additional risk factor for progression to mechanical ventilation: 1) arterial hypertension, 2) \>50 years, 3) obesity (bmi\>30.0 kg/m2), 4) history of cardiovascular disease, 5) chronic pulmonary disease, 7) chronic renal disease, 6) c-reactive protein of \>35mg/l, 7) oxygen saturation at rest in ambient air of \<94%

inclusion criteria: * age 18-85 years, * admitted to the hospital because of confirmed positive sars-cov-2 (covid-19 infection). * evidence of pulmonary involvement on ct scan or x-ray of the chest, * symptom onset within the previous 10 days and at least one additional risk factor for progression to mechanical ventilation: 1) arterial hypertension, 2) \>50 years, 3) obesity (bmi\>30.0 kg/m2), 4) history of cardiovascular disease, 5) chronic pulmonary disease, 7) chronic renal disease, 6) c-reactive protein of \>35mg/l, 7) oxygen saturation at rest in ambient air of \<94%

inclusion criteria: - age 18-85 years, - admitted to the hospital because of confirmed positive sars-cov-2 (covid-19 infection). - evidence of pulmonary involvement on ct scan or x-ray of the chest, - symptom onset within the previous 10 days and at least one additional risk factor for progression to mechanical ventilation: 1) arterial hypertension, 2) >50 years, 3) obesity (bmi>30.0 kg/m2), 4) history of cardiovascular disease, 5) chronic pulmonary disease, 7) chronic renal disease, 6) c-reactive protein of >35mg/l, 7) oxygen saturation at rest in ambient air of <94%

inclusion criteria: - age 18-85 years, - admitted to the hospital because of confirmed positive sars-cov-2 (covid-19 infection). - evidence of pulmonary involvement on ct scan or x-ray of the chest, - symptom onset within the previous 10 days and at least one additional risk factor for progression to mechanical ventilation: 1) arterial hypertension, 2) >50 years, 3) obesity (bmi>30.0 kg/m2), 4) history of cardiovascular disease, 5) chronic pulmonary disease, 7) chronic renal disease, 6) c-reactive protein of >35mg/l, 7) oxygen saturation at rest in ambient air of <94%