Effectiveness of Empiric Antiviral Treatment for Hospitalized Community Acquired Pneumonia during the Influenza Season (U18)

Current adult community acquired pneumonia (CAP) treatment guidelines recommend empiric broad-spectrum antibiotics that are effective against common bacterial agents. The initiation of antibiotics does not require laboratory confirmation of a bacterial etiology but is based upon data from published CAP etiology studies. Despite studies that have identified influenza as an important etiological agent of adult hospitalized patients with CAP, especially during peak influenza circulation, anti-influenza antiviral agents are uncommonly used empirically for CAP. In addition, novel influenza A (H1N1) has been documented to cause primary viral pneumonia in a majority of deaths with extensive testing of autopsy specimens. Most clinicians wait for laboratory confirmation of influenza infection before considering antiviral therapy. However, in routine clinical practice, diagnostic testing for influenza is uncommon, commonly used rapid testing methods have low sensitivity, and more sensitive diagnostic assays such as RT-PCR are not readily available. Also, even influenza RT-PCR assays performed on respiratory specimens are not always optimal for the detection of influenza infection and results of testing may take several days, after which the benefit if initiating antivirals goes down since the medications are of greatest benefit the earlier they are initiated after illness onset from influenza. Studies in Thailand have demonstrated that an additional 10-20% of acute influenza cases were identified with serologic assays, in addition to RT-PCR techniques on nasopharyngeal specimens.Thus, the use of empiric antiviral therapy, in addition to empiric antibiotic therapy, may be warranted, especially during a period when influenza viruses are circulating in the community.