Preventive effectiveness of nasal interferon-gamma among adult volunteers against acute respiratory viral infections, including COVID-19

Background. In vitro studies showed effective viral infection block in case of pretreatment with exogenous interferons. Interferon-gamma is a unique immune interferon, actively expressed in patients with acute respiratory viral infections (ARVI) and defending the body from severe infection course. Aim - to evaluate the safety and preventive effectiveness of nasal interferon-gamma protecting against ARVI, including COVID-19. Material and methods. The study enrolled 630 adult volunteers with a negative PCR test result for SARS-CoV-2, without respiratory symptoms and contraindications to interferongamma. Participants were randomized (1 : 1) into 2 groups: the study group - with the use of a prophylactic course of nasal interferon-gamma, and the group of comparison - without a course of prophylaxis. All participants were given a diary for daily monitor respiratory symptoms, adverse events, and record the use of pharmacotherapy. Results. Safety analysis found no differences between groups. During 28 days period a higher incidence of ARVI, including COVID-19, was observed in the group of comparison (13 vs 3 cases in the study group). The odd ratio was 0.224 (95 % CI: 0.040-0.826), p = 0.020. The total number of ARVI cases, including COVID-19, in the group of comparison during 2 months of research was 26 vs 6 in the study group. The odd ratio was 0.233 (95 % CI: 0.077- 0.594), p = 0,001. The longest period of persistence of respiratory symptoms was obtained in the group of comparison (7 vs 4 days in the study group, p = 0.034). Conclusion. Nasal interferon-gamma as a preventive measure contributes to a decrease of infection incidence of ARVI, including COVID-19.