Efficacy and Safety of Umifenovir (Arbidol) in Children with Influenza-like Illnesses: A Systematic Review and Meta-Analysis

Background: Pediatric influenza-like illness (ILI) represents a major global health burden. However, international treatment guidelines lack robust evidence specific to children. Umifenovir (Arbidol) is a broad-spectrum antiviral approved for pediatric use in several countries, but clinical data are fragmented and regionally limited. Methods: A comprehensive search of PubMed, Russian (RSCI, national archives, regulatory documents), and Chinese (CNKI) databases was conducted for pediatric randomized controlled trials (RCTs) and non-randomized trials comparing umifenovir to symptomatic therapy (ST) or oseltamivir. Risk of bias was assessed using the RoB 2 tool for RCTs, and ROBINS-I for non-RCTs. Outcomes included the duration of fever and other symptoms, prophylactic efficacy, and adverse events. Random-effects models were used (Hartung–Knapp–Sidik–Jonkman approach). The review was not registered. Results: We included 16 therapeutic and eight prophylactic trials enrolling approximately 4700 and 2000 children, respectively. Compared with ST, umifenovir reduced the duration of fever (MD −1.41 days, 95% CI: −1.78 to −1.05), cough (−1.15 days, 95% CI: −1.50 to −0.79), and hospitalization. The complication risk decreased (RR 0.34, 95% CI: 0.23–0.51). For prophylaxis, umifenovir reduced the risk of ILI (RR 0.68, 95% CI: 0.54–0.87) and laboratory-confirmed influenza (RR 0.41, 95% CI: 0.29–0.59). Adverse events were generally mild and did not differ significantly from ST or oseltamivir (RR 0.78, 95% CI: 0.51–1.20). Conclusions: Umifenovir may reduce symptom duration, complications, and infection risk in pediatric ILI, with a favorable safety profile. However, the overall certainty of evidence is limited by the age of the studies, geographic restriction, and methodological quality.