This is a multicenter prospective, randomized, double-blind, placebo-controlled, parallel-group phase 3 IIb\IIIa trial to evaluate the efficacy of Polyoxidonium, lyophilizate for solution for injections and topical application, 6 mg over placebo in hospitalized patients with coronavirus disease (COVID-19). A study will last for 293 days (maximum) for each participant and will include: screening (days -1...1); treatment period (17 days in total, days 1...17) with the administration of the investigational product Polyoxidonium/placebo (intravenous injections for 3 days, then intramuscular injections for 14 days), assessment of the clinical status, recording of AEs; follow-up period (days 18...293).
Haematology and blood chemistry tests will be performed at day -1 and days 1,3, 8 1, 171.
Assessment of the clinical status according to the 7-point ordinal scale and according to the National Early Warning Score (NEWS) scale will be done every day during hospitalization from day 1 up to and including day 17 and at the follow-up on day 293.
The safety and tolerability will be evaluated throughout the study (from signing the Informed Consent Form to the study completion visit).
