Influenza has been well established as a potentially dangerous pathogen and common cause for clinic visits in the United States. Antiviral treatment within 2 days of the onset of influenza symptoms has been shown to reduce the probability of associated complications. Few studies, however, have assessed antiviral use for influenza in the outpatient setting.

Taking a Closer Look

For a study published in Clinical Infectious Diseases, Fiona Havers, MD, MHS, and colleagues analyzed data on antiviral receipt among outpatients aged 6 months and older with acute respiratory illness as well as antibiotic receipt among patients diagnosed with influenza. Participants included patients who presented during the 2012-2013 flu season to one of five sites in the CDC’s ongoing U.S. Influenza Vaccine Effectiveness Study.

“We consider children younger than 2 years, adults aged 65 and older, those with a chronic medical condition, pregnant women, patients who were immunocompromised such as those with HIV or AIDS, and people of Native American, Alaska Native, or Pacific Islander race to be at increased risk for influenza complications,” explains Dr. Havers. “All these patients are recommended to promptly receive antiviral treatment if they present with flu-like symptoms.”

According to the study results, only 19% of high-risk patients who presented for care within 2 days of flu symptom onset received antiviral treatment, regardless of laboratory testing results and despite guidelines suggesting that they would benefit from such treatment. Among all patients with polymerase chain reaction-confirmed influenza, 15% received an antiviral prescription. Overall, fewer than 8% of participants received an antiviral prescription. “In contrast, we found that 30% of outpatients who had influenza, based on laboratory testing, received one of three antibiotics examined in the study,” says Dr. Havers. “Many most likely received antibiotics inappropriately.”

Important Considerations

According to Dr. Havers, the findings suggest some clinicians may not be aware that outpatients who are at high risk for influenza-associated complications are recommended to receive antiviral treatment if they present during flu season with symptoms that are consistent with influenza. “Many clinicians are aware that antiviral medications work best if prescribed during the first 48 hours because they stop viral replication,” she adds, “so they’re reluctant to prescribe antivirals after that window of time, when many patients present.”

While antivirals may still benefit those with severe progressive illness after 48 hours, Dr. Havers encourages clinicians to educate high-risk patients to call their provider promptly if they develop flu-like symptoms. “During flu season,” she says, “clinicians should be thinking of influenza as a possible diagnosis and about whether or not patients—particularly those at high risk for complications—could benefit from antiviral medication.”