Nasal recombinant human interferon alfa-2b in ARI

INTERVENTION: Administration, Intranasal Interferon alpha Interferon alpha‐2 Interferons Nasalferon, drops Placebos Stage I. Group A (Experimental): 2 drops (0.10 mL, 500,000 IU Nasalferon) in each nostril, 2 times a day, for 10 days. Total daily dose: 2 million IU. Group B (Experimental): 1 drop (0.05 mL, 250,000 IU Nasalferon) in each nostril, 2 times a day, for 10 days. Total daily dose: 1 million IU. Group C (Control): 2 drops (0.10 mL, placebo) in each nostril, 2 times a day, for 10 days. Group D (control): 1 drop (0.05 mL, placebo) in each nostril, 2 times a day, for 10 days. Stage II. Group E (Experimental): Variant selected from stage I, for 10 days. Group F (Control): Placebo with the dose administration scheme of the selected variant, for 10 days. CONDITION: acute respiratory infection Infections Respiratory Tract Diseases Respiratory Tract Infections PRIMARY OUTCOME: Patient recovery (Patient recovered: PCR negative for ARI of viral etiology and absence of clinical symptoms of ARI. Patient not recovered: PCR positive for ARI of viral etiology or presence of clinical symptoms of ARI). Measurement time: 3rd day, 8th day and 10th day after starting the treatment SECONDARY OUTCOME: 1.‐ Clinical response (disappearance of clinical respiratory symptoms). Measurement time: Daily during the patient's treatment time. 2.‐ Virological response (negative PCR for ARI of viral etiology). Measurement time: on the 8th and 11th day after starting treatment. 3.‐ Severity of the disease (Classification of the disease into mild, moderate, severe and critical stages). Measurement time: Daily during the patient's treatment time. 4. Post‐treatment clinical response (absence of clinical respiratory symptoms since the previous evaluation). Measurement time: on day 28 (week 4), day 56 (week 8) and day 84 (week 12) after the treatment was completed. 5. Security variables (Detection of adverse events during the physical examination of the patient or referrals). Measurement time: Daily during the patient's treatment time INCLUSION CRITERIA: 1.‐ Clinical diagnosis of ARI with mild symptoms (non‐sustained fever = 38 ºC, cough, sore throat, sneezing, nasal congestion, mild headache, mild body pain, malaise, diarrhea and/or vomiting. White nasal discharge (clear) or transparent Radiology (Rx) normal Oxygen saturation greater than 95%). 2.‐ Age between 19 and 80 years, regardless of gender or skin color. 3.‐ Time not greater than 48 hours from the onset of clinical respiratory symptoms. 4.‐ Voluntary nature of the patient to participate in the trial.