* severe respiratory failure at the time of screening due to covid-19 pneumonia; * known to undergo medical resuscitation for 14 days before randomization; * any serious medical condition or deviation of the clinical laboratory parameter that, in the opinion of the researcher, prevents safe participation and completion of the study by the participant confirmed uncontrolled active bacterial, fungal, viral or other infection (other than sars-cov-2). * according to the researcher, the progression to death is inevitable and will occur within the next 24 hours, regardless of the therapy. * the life expectancy of fewer than 28 days, taking into account a medical condition already existing that cannot be corrected, e.g. participants with the following conditions or suspicions: polyorganic insufficiency, poorly controlled neoplasms, terminal stage heart disease, cardiopulmonary cardiac arrest that required cardiopulmonary resuscitation, or electrical activity not accompanied by a pulse, or asystole within the last 30 days, terminal stage liver disease, terminal stage liver disease, or liver disease; * pregnancy or breastfeeding; * liver function failure (class c for child-pugh), detected within 24 hours at screening (local laboratory); * absolute neutrophil count (anc) \<500 cells/µl at screening (local laboratory); * platelet count \<50000 cells/µl at screening (based on laboratory data); * creatinine level ≥ 1.5 from the upper limit; * uncontrolled or untreated arrhythmia with clinical manifestations, myocardial infarction within the last 6 weeks or congestive heart failure (nyha degrees 3 or 4); * respiratory failure in the last 6 months or home use of oxygen in severe chronic respiratory disease (copd); * quadriplegia; * primary immunodeficiency, tuberculosis, progressive multifocal leukoencephalopathy, aspergillosis or other invasive mold/fungal infection in anamnesis, or internal or bone marrow transplantation for 6 months before randomization; * known infection with hepatitis b or c viruses requiring therapy;

* severe respiratory failure at the time of screening due to covid-19 pneumonia; * known to undergo medical resuscitation for 14 days before randomization; * any serious medical condition or deviation of the clinical laboratory parameter that, in the opinion of the researcher, prevents safe participation and completion of the study by the participant confirmed uncontrolled active bacterial, fungal, viral or other infection (other than sars-cov-2). * according to the researcher, the progression to death is inevitable and will occur within the next 24 hours, regardless of the therapy. * the life expectancy of fewer than 28 days, taking into account a medical condition already existing that cannot be corrected, e.g. participants with the following conditions or suspicions: polyorganic insufficiency, poorly controlled neoplasms, terminal stage heart disease, cardiopulmonary cardiac arrest that required cardiopulmonary resuscitation, or electrical activity not accompanied by a pulse, or asystole within the last 30 days, terminal stage liver disease, terminal stage liver disease, or liver disease; * pregnancy or breastfeeding; * liver function failure (class c for child-pugh), detected within 24 hours at screening (local laboratory); * absolute neutrophil count (anc) \<500 cells/µl at screening (local laboratory); * platelet count \<50000 cells/µl at screening (based on laboratory data); * creatinine level ≥ 1.5 from the upper limit; * uncontrolled or untreated arrhythmia with clinical manifestations, myocardial infarction within the last 6 weeks or congestive heart failure (nyha degrees 3 or 4); * respiratory failure in the last 6 months or home use of oxygen in severe chronic respiratory disease (copd); * quadriplegia; * primary immunodeficiency, tuberculosis, progressive multifocal leukoencephalopathy, aspergillosis or other invasive mold/fungal infection in anamnesis, or internal or bone marrow transplantation for 6 months before randomization; * known infection with hepatitis b or c viruses requiring therapy;

- severe respiratory failure at the time of screening due to covid-19 pneumonia; - known to undergo medical resuscitation for 14 days before randomization; - any serious medical condition or deviation of the clinical laboratory parameter that, in the opinion of the researcher, prevents safe participation and completion of the study by the participant confirmed uncontrolled active bacterial, fungal, viral or other infection (other than sars-cov-2). - according to the researcher, the progression to death is inevitable and will occur within the next 24 hours, regardless of the therapy. - the life expectancy of fewer than 28 days, taking into account a medical condition already existing that cannot be corrected, e.g. participants with the following conditions or suspicions: polyorganic insufficiency, poorly controlled neoplasms, terminal stage heart disease, cardiopulmonary cardiac arrest that required cardiopulmonary resuscitation, or electrical activity not accompanied by a pulse, or asystole within the last 30 days, terminal stage liver disease, terminal stage liver disease, or liver disease; - pregnancy or breastfeeding; - liver function failure (class c for child-pugh), detected within 24 hours at screening (local laboratory); - absolute neutrophil count (anc) <500 cells/µl at screening (local laboratory); - platelet count <50000 cells/µl at screening (based on laboratory data); - creatinine level ≥ 1.5 from the upper limit; - uncontrolled or untreated arrhythmia with clinical manifestations, myocardial infarction within the last 6 weeks or congestive heart failure (nyha degrees 3 or 4); - respiratory failure in the last 6 months or home use of oxygen in severe chronic respiratory disease (copd); - quadriplegia; - primary immunodeficiency, tuberculosis, progressive multifocal leukoencephalopathy, aspergillosis or other invasive mold/fungal infection in anamnesis, or internal or bone marrow transplantation for 6 months before randomization; - known infection with hepatitis b or c viruses requiring therapy;

- severe respiratory failure at the time of screening due to covid-19 pneumonia; - known to undergo medical resuscitation for 14 days before randomization; - any serious medical condition or deviation of the clinical laboratory parameter that, in the opinion of the researcher, prevents safe participation and completion of the study by the participant confirmed uncontrolled active bacterial, fungal, viral or other infection (other than sars-cov-2). - according to the researcher, the progression to death is inevitable and will occur within the next 24 hours, regardless of the therapy. - the life expectancy of fewer than 28 days, taking into account a medical condition already existing that cannot be corrected, e.g. participants with the following conditions or suspicions: polyorganic insufficiency, poorly controlled neoplasms, terminal stage heart disease, cardiopulmonary cardiac arrest that required cardiopulmonary resuscitation, or electrical activity not accompanied by a pulse, or asystole within the last 30 days, terminal stage liver disease, terminal stage liver disease, or liver disease; - pregnancy or breastfeeding; - liver function failure (class c for child-pugh), detected within 24 hours at screening (local laboratory); - absolute neutrophil count (anc) <500 cells/µl at screening (local laboratory); - platelet count <50000 cells/µl at screening (based on laboratory data); - creatinine level ≥ 1.5 from the upper limit; - uncontrolled or untreated arrhythmia with clinical manifestations, myocardial infarction within the last 6 weeks or congestive heart failure (nyha degrees 3 or 4); - respiratory failure in the last 6 months or home use of oxygen in severe chronic respiratory disease (copd); - quadriplegia; - primary immunodeficiency, tuberculosis, progressive multifocal leukoencephalopathy, aspergillosis or other invasive mold/fungal infection in anamnesis, or internal or bone marrow transplantation for 6 months before randomization; - known infection with hepatitis b or c viruses requiring therapy;