Background: Seasonal influenza causes an estimated 100,000–710,000 hospitalizations annually in the United States (U.S.). Treatment with antiviral medications, such as oseltamivir, can reduce risks of hospitalization among people with influenza-associated illness. The U.S. Centers for Disease Control and Prevention recommends initiating antiviral treatment as soon as possible for outpatients with suspected or confirmed influenza who have severe or progressive illness or are at higher risk of influenza complications.
Methods: We developed a probabilistic model to estimate the impact of antiviral treatment in reducing hospitalizations among U.S. outpatients with influenza. Parameters were informed by seasonal influenza surveillance platforms and stratified by age group and whether individuals had a medical condition associated with higher risk of influenza complications. We modeled different scenarios for influenza antiviral effectiveness and outpatient testing and prescribing practices, then compared our results to a baseline scenario in which antivirals were not used.
Results: Across the modeled scenarios, antiviral treatment resulted in 1,215–14,184 fewer influenza-associated hospitalizations on average compared to the baseline scenario (a 0.2%–2.7% reduction). The greatest effects occurred among adults ≥65 years and individuals with conditions associated with higher risk of influenza complications. Modeling 50% improvements in access to care, testing, prescribing, and treatment resulted in greater potential impacts, with over 71,000 (13.3%) influenza-associated hospitalizations averted on average compared to baseline.
Conclusions: Our results support recommendations to prioritize outpatient antiviral treatment among older adults and others at higher risk of influenza complications. Improving access to prompt testing and treatment among outpatients with suspected influenza could reduce hospitalizations substantially
*Contributed equally