inclusion criteria: * recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. * confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. * in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (\<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. * presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation * signs of cytokine release syndrome defined as any of the following: 1. serum ferritin concentration \>1000 mcg/l and rising since last 24h 2. single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation 3. lymphopenia defined as \<800 lymphocytes/microliter) and two of the following extra criteria * ferritin \> 700 mcg/l and rising since last 24h * increased ldh (above 300 iu/l) and rising last 24h * d-dimers \> 1000 ng/ml and rising since last 24h * crp above 70mg/l and rising since last 24h and absence of bacterial infection * if three of the above are present at admission, no need to document 24h rise * chest x-ray or ct scan showing bilateral infiltrates within last 2 days * admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients * age ≥ 18yrs * male or female * willing and able to provide informed consent or legal representative willing to provide informed consent

inclusion criteria: * recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. * confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. * in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (\<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. * presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation * signs of cytokine release syndrome defined as any of the following: 1. serum ferritin concentration \>1000 mcg/l and rising since last 24h 2. single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation 3. lymphopenia defined as \<800 lymphocytes/microliter) and two of the following extra criteria * ferritin \> 700 mcg/l and rising since last 24h * increased ldh (above 300 iu/l) and rising last 24h * d-dimers \> 1000 ng/ml and rising since last 24h * crp above 70mg/l and rising since last 24h and absence of bacterial infection * if three of the above are present at admission, no need to document 24h rise * chest x-ray or ct scan showing bilateral infiltrates within last 2 days * admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients * age ≥ 18yrs * male or female * willing and able to provide informed consent or legal representative willing to provide informed consent

inclusion criteria: recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation signs of cytokine release syndrome defined as any of the following: serum ferritin concentration >1000 mcg/l and rising since last 24h single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation lymphopenia defined as <800 lymphocytes/microliter) and two of the following extra criteria ferritin > 700 mcg/l and rising since last 24h increased ldh (above 300 iu/l) and rising last 24h d-dimers > 1000 ng/ml and rising since last 24h crp above 70mg/l and rising since last 24h and absence of bacterial infection if three of the above are present at admission, no need to document 24h rise chest x-ray or ct scan showing bilateral infiltrates within last 2 days admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients age ≥ 18yrs male or female willing and able to provide informed consent or legal representative willing to provide informed consent

inclusion criteria: recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation signs of cytokine release syndrome defined as any of the following: serum ferritin concentration >1000 mcg/l and rising since last 24h single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation lymphopenia defined as <800 lymphocytes/microliter) and two of the following extra criteria ferritin > 700 mcg/l and rising since last 24h increased ldh (above 300 iu/l) and rising last 24h d-dimers > 1000 ng/ml and rising since last 24h crp above 70mg/l and rising since last 24h and absence of bacterial infection if three of the above are present at admission, no need to document 24h rise chest x-ray or ct scan showing bilateral infiltrates within last 2 days admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients age ≥ 18yrs male or female willing and able to provide informed consent or legal representative willing to provide informed consent

inclusion criteria: - recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. - confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. - in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. - presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation - signs of cytokine release syndrome defined as any of the following: 1. serum ferritin concentration >1000 mcg/l and rising since last 24h 2. single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation 3. lymphopenia defined as <800 lymphocytes/microliter) and two of the following extra criteria - ferritin > 700 mcg/l and rising since last 24h - increased ldh (above 300 iu/l) and rising last 24h - d-dimers > 1000 ng/ml and rising since last 24h - crp above 70mg/l and rising since last 24h and absence of bacterial infection - if three of the above are present at admission, no need to document 24h rise - chest x-ray or ct scan showing bilateral infiltrates within last 2 days - admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients - age ≥ 18yrs - male or female - willing and able to provide informed consent or legal representative willing to provide informed consent

inclusion criteria: - recent ( ≥ 6 days of flu-like symptoms or malaise yet ≤16 days of flu-like symptoms or malaise prior to randomization) infection with covid-19. - confident covid-19 diagnosis confirmed by antigen detection test and/or pcr and/or positive serology, or any emerging and validated diagnostic laboratory test for covid-19 within this period. - in some patients, it may be impossible to get a confident laboratory confirmation of covid-19 diagnosis after 24h of hospital admission because viral load is low and/or problems with diagnostic sensitivity. in those cases, in absence of an alternative diagnosis, and with highly suspect bilateral ground glass opacities on recent (<24h) chest-ct scan (confirmed by a radiologist and pulmonary physician as probable covid-19), and a typical clinical and chemical diagnosis with signs of cytokine release syndrome, a patient can be enrolled as probable covid-19 infected. in all cases, this needs confirmation by later seroconversion. - presence of hypoxia defined as pao2/fio2 below 350 while breathing room air in upright position or pao2/fio2 below 280 on supplemental oxygen and immediately requiring high flow oxygen device or mechanical ventilation - signs of cytokine release syndrome defined as any of the following: 1. serum ferritin concentration >1000 mcg/l and rising since last 24h 2. single ferritin above 2000 mcg/l in patients requiring immediate high flow oxygen device or mechanical ventilation 3. lymphopenia defined as <800 lymphocytes/microliter) and two of the following extra criteria - ferritin > 700 mcg/l and rising since last 24h - increased ldh (above 300 iu/l) and rising last 24h - d-dimers > 1000 ng/ml and rising since last 24h - crp above 70mg/l and rising since last 24h and absence of bacterial infection - if three of the above are present at admission, no need to document 24h rise - chest x-ray or ct scan showing bilateral infiltrates within last 2 days - admitted to specialized covid-19 ward or an icu ward taking care of covid-19 patients - age ≥ 18yrs - male or female - willing and able to provide informed consent or legal representative willing to provide informed consent