Purpose of the study:

• To obtain additional data on the efficacy and safety of Anaferon in the treatment of acute respiratory viral infections.

Design: a multicenter, double-blind, placebo-controlled, parallel-group randomized trial.

The study will enroll patients of either gender aged 18-70 years old with clinical manifestations of ARVI within the first day after the onset of the disease. Signed information sheet for patient will be obtained from all participants prior to the screening procedures. Medical history, concomitant medication, thermometry, patient examination by a doctor, assessment of ARVI symptoms severity will be performed at screening visit.

The nasopharyngeal swabs will be performed for Real-time reverse transcription polymerase chain reaction (PCR) assay to confirm viral etiology of ARVI and to verify respiratory viruses prior to the therapy.

If a patient meets all inclusion criteria and does not have any exclusion criteria, at Visit 1 (Day 1) he/she will be randomized into one of two groups: the 1st group patients will take Anaferon according to the dosage regimen until the end of the study; the 2nd group patients will take Placebo according to Anaferon dosage regimen until the end of the study.

The patients will be provided with a patient diary (paper or electronic) where daily they will record axillary body temperature (using a Geratherm Classic thermometer) and each ARVI symptom severity twice a day (in the morning and in the evening). In addition, antipyretic administration (if applicable) as well as any possible worsening of the patient's condition (if applicable, for safety evaluation/AEs documentation) will also be recorded in a patient diary. An investigator will provide the instructions on filling out the diary and will help the patient to make first records of ARVI symptom severity and body temperature in the diary.

Patients are observed up for 7 days (screening, randomization - 1 day, study therapy - 5 days, follow-up period - 2 days). During treatment and follow-up period two visits are scheduled (at home or at the study site) on days 5 (Visit 2) and day 7 (Visit 3). At Visits 2 and 3, the investigator will carry out physical examination, record dynamics of ARVI symptoms and concomitant therapy and check patient diaries.

Treatment compliance will be evaluated at Visit 3. During the study, symptomatic therapy and therapy for underlying chronic conditions are allowed with the exception of the drugs indicated in the section "Prohibited Concomitant Treatment".

Inclusion Criteria:

1. Patients of either gender aged 18-70 years.
2. Diagnosis of acute respiratory viral infection (ARVI) based on medical examination: axillary temperature ≥ 37,8 ° C at examination + non-specific/flu-like symptom score ≥4, nasal/throat/chest symptom score ≥2.
3. The first 24 hours after ARVI onset.
4. Seasonal rise in ARVI incidence.
5. Patients giving their consent to use reliable contraception during the study.
6. Signed patient information sheet (informed consent form).

Exclusion Criteria:

1. Suspected pneumonia, bacterial infection (including otitis media, sinuitis, urinary tract infection, meningitis, sepsis, etc.), requiring the administration of antibacterial drugs from the first day of the disease.
2. Suspected initial manifestations of diseases with symptoms similar to ARVI at onset (other infectious diseases, flu-like syndrome at the onset of systemic diseases of connective tissue, oncohaematological and other diseases).
3. Clinical symptoms of severe influenza/ARVI requiring hospitalization.
4. Subjects requiring concurrent antiviral products forbidden by the study.
5. Medical history of primary and secondary immunodeficiency.
6. Oncologic conditions /suspected oncologic conditions.
7. Aggravation or decompensation of chronic diseases affecting a patient's ability to participate in the clinical trial.
8. Impaired glucose tolerance, diabetes mellitus.
9. Malabsorption syndrome, including congenital or acquired lactase or other disaccharidase deficiency, galactosemia.
10. Allergy/ hypersensitivity to any component of the study drug.
11. Pregnancy, breast-feeding; childbirth less than 3 months prior to the inclusion in the trial, unwillingness to use contraceptive methods during the trial.
12. Consumption of narcotics, alcohol > 2 alcohol units per day, mental diseases.
13. Course administration of the drug products specified in the section "Prohibited Concomitant Therapy" within two weeks prior to inclusion in the study.
14. Patients who will not fulfill the requirements during the study or follow the order of administration of the studied drug products, from the Investigator's point of view.
15. Participation in other clinical trials for 3 months prior to enrollment in this study.
16. Patients who are related to any of the on-site research personnel directly involved in the study or are an immediate relative of the investigator. 'Immediate relative' means husband, wife, parent, son, daughter, brother, or sister (regardless of whether they are natural or adopted).
17. Patients who work for OOO "NPF "Materia Medica Holding" (i.e. the company's employees, temporary contract workers, designated officials responsible for carrying out the research or any immediate relatives of the aforementioned).