inclusion criteria: i (first step): * admission to hospital * male or non-pregnant female, ≥60 years of age or ≥30 years of age plus one or more known risk factors (arterial hypertension, diabetes mellitus, coronary heart disease, heart failure, pre-existing chronic pulmonary disease) * confirmed sars-cov infection * radiographic evidence compatible with covid-19 pneumonia (x-ray/ct scan, etc.) * signed informed consent form ii (second step; indication for intervention): * crp ≥50mg/l plus 3 out of the following 5 criteria need to be fulfilled: * respiration rate ≥25 * spo2 \<93% (on ambient air) * pao2 \<65 mmhg * persistent or increasing dyspnoea as defined by a one point increase on the mmrc dyspnoea scale (over 1 hour) * persistent or increasing oxygen demand (over 1 hour)

inclusion criteria: i (first step): * admission to hospital * male or non-pregnant female, ≥60 years of age or ≥30 years of age plus one or more known risk factors (arterial hypertension, diabetes mellitus, coronary heart disease, heart failure, pre-existing chronic pulmonary disease) * confirmed sars-cov infection * radiographic evidence compatible with covid-19 pneumonia (x-ray/ct scan, etc.) * signed informed consent form ii (second step; indication for intervention): * crp ≥50mg/l plus 3 out of the following 5 criteria need to be fulfilled: * respiration rate ≥25 * spo2 \<93% (on ambient air) * pao2 \<65 mmhg * persistent or increasing dyspnoea as defined by a one point increase on the mmrc dyspnoea scale (over 1 hour) * persistent or increasing oxygen demand (over 1 hour)

inclusion criteria: i (first step): - admission to hospital - male or non-pregnant female, ≥60 years of age or ≥30 years of age plus one or more known risk factors (arterial hypertension, diabetes mellitus, coronary heart disease, heart failure, pre-existing chronic pulmonary disease) - confirmed sars-cov infection - radiographic evidence compatible with covid-19 pneumonia (x-ray/ct scan, etc.) - signed informed consent form ii (second step; indication for intervention): - crp ≥50mg/l plus 3 out of the following 5 criteria need to be fulfilled: - respiration rate ≥25 - spo2 <93% (on ambient air) - pao2 <65 mmhg - persistent or increasing dyspnoea as defined by a one point increase on the mmrc dyspnoea scale (over 1 hour) - persistent or increasing oxygen demand (over 1 hour)

inclusion criteria: i (first step): - admission to hospital - male or non-pregnant female, ≥60 years of age or ≥30 years of age plus one or more known risk factors (arterial hypertension, diabetes mellitus, coronary heart disease, heart failure, pre-existing chronic pulmonary disease) - confirmed sars-cov infection - radiographic evidence compatible with covid-19 pneumonia (x-ray/ct scan, etc.) - signed informed consent form ii (second step; indication for intervention): - crp ≥50mg/l plus 3 out of the following 5 criteria need to be fulfilled: - respiration rate ≥25 - spo2 <93% (on ambient air) - pao2 <65 mmhg - persistent or increasing dyspnoea as defined by a one point increase on the mmrc dyspnoea scale (over 1 hour) - persistent or increasing oxygen demand (over 1 hour)