An Open Non-comparative Study of the Efficacy and Safety of Aprotinin in Patients Hospitalized With COVID-19

Primary objective of the study is to evaluate the efficacy of Aprotinin as add-on therapy in patients hospitalized with COVID-19 using the following parameters: * The time to elimination of SARS-CoV-2 virus until Day 10; * The time to C-reactive protein (CRP) normalization until Day 10; * The time to D-dimer normalization until Day 10. Secondary objectives are to evaluate the following parameters of efficacy and safety of Aprotinin add-on therapy in patients hospitalized with COVID-19: * The time to body temperature normalization (\<37oC); * Changes from baseline of the laboratory parameters during 14 days: hematology, CRP, coagulogram; * Changes of lung injury on CT scan on Day 7 and Day 14 from baseline; * Frequency of clinical status improvement by 2 scores in accordance with the WHO Ordinal scale of clinical improvement (WHO-OSCI) or discharge from the hospital before Day 14; * Frequency of transfer to the Intensive Care Unit (ICU), frequency of the non-invasive ventilation, frequency of the invasive ventilation and mortality rate; * Frequency of Adverse Events (AEs) and Serious Adverse Events (SAEs) of various severity according to subjective complains, physical examination, vital signs, laboratory tests and ECG.