Prevention of acute respiratory viral infections and influenza in children during the peaks of seasonal morbidity: the results of the international double-blind placebo-controlled randomized clinical trial

The authors conducted an international multicenter double-blind, placebo-controlled clinical study to obtain additional data on the efficacy and safety of a 12-week course of Anaferon for children for the prevention of acute respiratory viral infections (ARVI), including influenza, in children during the rise in seasonal morbidity (RCT of the Ministry of Health of the Russian Federation: №356 dated June 29, 2017; ClinicalTrials.gov Identifier: NCT03301155). Materials and methods. The study involved 1,036 children (1 month – 6 years 11 months 29 days) during two epidemiological seasons. The patients were divided into 2 groups: 528 patients received Anaferon for children 1 tablet a day for 12 weeks, 508 patients received placebo according to Anaferon for children scheme. The primary end point was the duration of the period from the first dose of the drug until manifestation of ARVI/influenza. Additional end points were percentage of children not falling with ARVI/influenza during 4-, 8- and 12-week course of preventive therapy; percentage of children with respiratory or ear-nose-throat bacterial infections requiring antibiotics within 12 week; percentage of children hospitalized with ARVI/influenza or their complications within 12 week. To assess safety, the authors analyzed the presence and nature of the adverse events (AEs), their severity, connection with the medication, outcome. The authors used the following statistical methods: calculation of hazard ratio, median time to the manifestation of symptoms of ARVI / influenza, 95% confidence intervals. Results. The Intention-to-treat (ITT) and Per Protocol [РР] analysis included the data of 1,021 [975] patients: 520 [494] – Anaferon for children group and 501 [481] –Placebo group. The average duration of the period from the first dose of the drug to the development of ARVI/influenza symptoms obtained as a result of the analysis of the statistical model was 428.8 [434.1] days for Anaferon for children group, that is 1.5 times higher than in Placebo group (275.8 [274.9] days; p=0.001 [p=0.0009]). The percentage of children without ARVI/influenza was 99.2% [99.2%] in Anaferon for children group (versus 90.2% [90.0%] in Placebo group; p=0.0003 [p=0.0003]) within 4 weeks, 92.7% [92.3%] (versus 82.8% [82.7%]; p=0.0003 [p=0.0003]) within 8 weeks, and 81.5% [81.8%] (versus 73.4% [73.4%], respectively; p=0.0021 [p=0.0021]). None of the patients was hospitalized for ARVI/influenza or complications. The frequency of AEs in Anaferon for children and Placebo groups had no differ. No one AE definitely related to the study drug was registered. Conclusion. The results confirm the efficacy and safety of a 12-week course of Anaferon for children to prevent ARVI and influenza during seasonal rise of morbidity in children.