OBJECTIVETo evaluate the efficacy and safety of Arbidol in the treatment of naturally acquired influenza.

METHODSA randomized, double-blinded, placebo controlled trial was conducted. Subjects were enrolled. The inclusion criteria included: aged 18 to 65 years, presented within 36 hours of onset of influenza symptoms; and had documented temperature of 37.8 degrees C or higher during an influenza outbreak in the community. Individuals were randomly divided Arbidol group (200 mg three times daily for 5 days) or placebo group.

RESULTSTotally 232 individuals were recruited and received medication and follow-up. All of them were qualified to be analyzed for safety as intent-to-treat population (ITT) (113 Arbidol, 109 placebo). Twenty-two (9.48%) were during follow-up or refused to continue the trial, and 210 completed as schecule and identified as PP population (102 Arbidol, 108 placebo). Totally 125 individuals were identified as influenza-infected through laboratory test, which was defined as PPi population (59 Arbidol, 66 placebo). In PPi population, the cumulative alleviation proportion of Arbidol group was significantly higher than that of placebo group. The median duration of illness was 72.0 hours (95% confident interval (CI) 66.00-78.00 hours) in Arbidol group and 96.0 hours (95% CI 87.46-104.54 hours) in placebo group. The median area under the curve (AUC) of decreased total score were significantly higher in Arbidol group than in placebo group, which were 780.00 and 684.00 score-hours respectively. For PP population, similar results were seen. Adverse events reported were similar in Arbidol group and in placebo group. The main adverse events were gastrointestial symptoms and increased transaminase.

CONCLUSIONArbidol was effective and well tolerated in the treatment of early naturally acquired influenza.