Jul 11, 2012 (CIDRAP News) – Researchers following recent antiviral trends in the United States have found a troubling drop in the use of the drugs for treating hospitalized patients with lab-confirmed flu, especially children.
They found that strong recommendations from medical organizations helped push use of the drugs in seriously ill patients to high levels during the 2009 H1N1 pandemic, but that levels fell the following flu season. The study, conducted by researchers from the US Centers for Disease Control and Prevention (CDC) and collaborators from several state health departments, appeared today in the latest issue of Clinical Infectious Diseases.
During the 2009 pandemic the CDC issued guidelines recommending that hospitalized children and adults with confirmed or suspected flu receive early antiviral treatment, regardless of underlying conditions. By the start of the 2010-11 season, the American Academy of Pediatrics (AAP) and the CDC's Advisory Committee on Immunization Practices (ACIP) followed up with the same recommendations.
Using population-based hospital data from the CDC's Influenza Surveillance Network (FluSurv-NET), the team compared the proportions of children and adults hospitalized with lab-confirmed flu infections who were treated with antivirals during the 2010-11 season and during the 2009 pandemic. Patients were included if they were hospitalized within 14 days after a positive influenza test result. Investigators reviewed medical charts to collect demographic, medical history, and clinical information.
Among nearly 9,000 patients identified in FluSurv-NET who were hospitalized with lab-confirmed flu during the 2009 pandemic, 77% of children received antiviral treatment and 82% of adults received the drugs. Researchers found that 99% of the treated patients got oseltamivir (Tamiflu).
However, the following flu season, among just over 6,000 patients hospitalized with lab-confirmed flu, the proportion of children who received antivirals dropped to 56% and the percentage of treated adults fell to 77%, according to the study.
Researchers said the drop from 2009 to the 2010-2011 season was significant for all age groups except those 65 years and older.
They found no drop for pregnant women hospitalized for flu, but children and adults with underlying medical conditions who were hospitalized for flu were significantly more likely to have received antivirals during the 2009 pandemic. Though similar proportions of children were admitted to intensive care units during flu hospitalization in both seasons, they were more likely to receive antivirals during the pandemic months.
The researchers wrote that the frequency of antiviral treatment for hospitalized flu patients hasn't sunk to prepandemic levels, but the findings suggest that important gains eroded in the season after the pandemic. They added that children younger than 2 years—the pediatric age-group at highest risk for flu complications—had the biggest decline between the two seasons.
More efforts are needed to sort out barriers to antiviral treatment for hospitalized patients, the authors said. For example, they pointed out that though oseltamivir dosing guidelines are available from the AAP and ACIP, the drug is not licensed for use in children younger than 1 year.
More strategies are needed to teach health providers about the benefits of antiviral treatment and highlight guidance on it, the investigators wrote.
Garg S, Chaves SS, Perez A, et al. Reduced influenza antiviral treatments among children and adults hospitalized with laboratory-confirmed influenza infection in the year after the 2009 pandemic. Clin Infect Dis 2012 Aug 1;55(3):e18-e21 [Abstract]