Evaluating the Use of Oseltamivir for the Treatment of Influenza in Adults

Seasonal influenza is responsible for excess hospitalizations and, despite effective antivirals, causes significant morbidity and mortality (about 24,000 deaths each year in the United States alone). The influenza virus that emerged in 2009 (A/California/07/2009 H1N1) caused fewer deaths (12,000 flu-related deaths in the U.S.) but in contrast to seasonal flu, nearly 90% of the deaths with the 2009 H1N1 occurred among people younger than 65 years of age. Although there are four currently licensed anti-influenza medications (amantadine and rimantadine, oseltamivir, and zanamivir), previous studies have not demonstrated conclusively to what extent these medications affect influenza viral shedding. This study will evaluate whether oseltamivir modifies the viral shedding during the treatment of uncomplicated influenza in an adult population and also assess methods to detect viral replication in the upper respiratory tract. Subjects who presented with an influenza-like illness without any risk factors for severe disease were screened for the study. Those with a confirmatory test for influenza (rapid antigen or polymerase chain reaction \[PCR\]) were randomized in a 1:1 manner to receive a blinded study treatment consisting of either the oseltamivir or placebo for 5 days. Clinical, virologic, and laboratory assessments on Days 1, 3, 7, and 28 were used for both safety and efficacy analysis.