Comparative Clinical Trial of Efficacy and Safety of Ergoferon Versus Oseltamivir in Treatment of Influenza

Inclusion Criteria: 1. Patients aged 18 to 70 years. 2. Patients who were admitted to hospital within 48 hours from the onset of influenza signs. 3. Patients with body temperature ≥37,8°C when visiting a doctor + severity of influenza symptoms ≥4 scores (presence of at least 1 non-specific flu symptom ≥2 scores and 1 nasal/ throat/ chest symptom ≥ 2 scores or greater number of symptoms with the severity ≥1 score). 4. Diagnosed influenza confirmed by rapid diagnostic test (OSOM Influenza A\&B Test). 5. The possibility to start therapy within 48 hours after the onset of the first symptoms of influenza. 6. Usage of contraceptive methods by both gender patients of reproductive age during the trial and within 30 days after ending the participation in the trial. 7. Availability of signed patient information sheet (Informed Consent form) for participation in the clinical trial. Exclusion Criteria: 1. Suspected pneumonia, bacterial infection or the presence of a severe disease requiring usage of antibacterial drugs (including sulphanilamides) starting from Day 1 of the disease. 2. Severe influenza with indications for hospitalization. 3. Suspected early manifestations of diseases that have symptoms similar to influenza symptoms (other acute respiratory and infectious diseases, influenza-like syndrome at the onset of systemic connective tissue disorders, hematologic neoplasms and other pathology). 4. Patients requiring concurrent antiviral products forbidden by the study. 5. Medical history of primary and secondary immunodeficiencies. а) lymphoid immunodeficiencies (Т-cell and/or В-cell, immunodeficiencies with predominant antibody deficit); b) phagocytic deficits; c) complement factor deficit; d) combined immunodeficiencies including AIDS secondary to HIV infection; toxic, autoimmune, infectious, radiation panleukopenic syndrome; total lymphocytopenic syndrome; polyclonal lymphocyte activation syndrome; postsplenectomic syndrome; congenital asplenia; abnormal immune complex syndrome associated with infectious, autoimmune and allergic diseases. 6. Medical history of sarcoidosis 7. An oncological disease/suspected oncological disease. 8. Exacerbated or decompensated chronic diseases affecting a patient's ability to participate in the clinical trial. 9. Medical history of polyvalent allergy. 10. Allergy/intolerance to any of the components of the product used for influenza therapy. 11. Impaired glucose tolerance, type 1 and type 2 diabetes mellitus. 12. Malabsorption syndrome, including congenital or acquired lactose deficiency or another disaccharide deficiency. 13. Pregnancy, breast-feeding. 14. Consumption of narcotics, alcohol \> 2 alcohol units per day, mental diseases. 15. Use of any medicine listed in the section "Prohibited concomitant treatment" within 30 days preceding the inclusion in this study. 16. Patients who, from the investigator's point of view, will fail to comply with the observation requirements of the trial or with the regimen of the study drugs. 17. Participation in other clinical studies within 1 month prior to enrollment in the current trial. 18. Patients related to the research staff of the clinical trial site who are directly involved in the trial or are the immediate family member of the researcher. The immediate family members include husband/wife, parents, children or brothers (or sisters), regardless of whether they are natural or adopted. 19. Patients employed with OOO "NPF "MATERIA MEDICA HOLDING" (i.e., the company's employee, part-time employee under contract, or appointed official in charge of the trial, or their immediate family).