Objective. A longitudinal cohort study was conducted to assess the effect of intranasal recombinant interferon α-2b-based medicine (Grippferon) on clinical, functional and immunological parameters in patients with concomitant bronchial asthma (BA) and allergic rhinitis (AR). Patients and methods. Twelve children aged between 10 and 17 years were examined. Clinical symptoms and nasal respiratory function, the content of VEGF, interleukins IL-1,-2,-4,-6, eosinophilic cationic protein (ECP) and total IgE in nasal secretions were assessed on days 1 and 31. Results. The study results showed a statistically significant increase in nasal respiratory flow (p = 0.001), a decrease in the severity of nasal (p = 0.002) and sinonasal symptoms (p = 0.0015), a reduction in VEGF concentration in nasal secretions (p = 0.014) and a downward trend in ECP (p = 0.09) and IL-4 (p = 0.10) levels. No statistically significant changes in IL-1, IL-6, and IgE content were found. Conclusion. The intranasal use of recombinant interferon α-2b-based medicine (Grippferon) for prevention of acute respiratory viral infections is well-tolerated by patients with AR and BA with shown notable improvement in nasal respiratory function, decrease in the severity of nasal and sinonasal symptoms and downward trends in the content of several T2 inflammation biomarkers in nasal secretions. © 2023, Dynasty Publishing House. All rights reserved.