Editorial Commentary: Failing Our Patients by Suboptimally Treating Influenza Infections

Influenza is an important cause of morbidity and mortality related to annual epidemics and intermittent pandemics of respiratory viral infections. Whereas most of the 25 million annual cases of influenza result in self-limited infections, influenza is responsible for an excess 31.4 million outpatient visits, 226 000 excess hospitalizations, and up to 48 614 excess deaths annually in the United States [1–5]. Risk factors for serious illness and death include age <2 years or ≥65 years, and medical conditions including compromised immunity, pregnancy, and morbid obesity [3, 5]. Influenza vaccination remains the most important tool in preventing influenza. Unfortunately, influenza vaccine rates remain suboptimal and breakthrough infections, despite appropriate vaccination, do occur [5, 6]. Antiviral therapy with one of the neuraminidase inhibitors (oseltamivir or zanamivir) is recommended for the treatment of patients who develop influenza infections [7, 8]. Prospective studies in ambulatory adults and children have demonstrated that the neuraminidase inhibitors are associated with shorter time to alleviation of illness and with reductions in severity of illness, duration of fever, time to return to normal activity, and quantity of shed virus [9]. Data also suggest that antiviral therapy is associated with reduction in the frequency of complications leading to antibiotic use, particularly bronchitis, compared with placebo in previously healthy adults [10–12]. In ambulatory adults and children, antiviral therapy is generally effective only if started within the first 48–72 hours after symptom onset [9, 13, 14].Moreover, earlier initiation of oral oseltamivir therapy is associated with increased therapeutic effects [13]. Data also suggest that antiviral therapy may be associated with fewer hospitalizations, particularly in high-risk patient populations [15].Among hospitalized patients, antiviral therapy is associated with reduced incidence of lower respiratory tract complications, requirement for intensive care, duration of illness, duration of shedding, and mortality. Although efficacy among patients requiring hospitalization is greatest with early therapy, antiviral therapy appears to be effective for at least 5 days after symptom onset [16, 17]. Despite the documented efficacy of antiviral therapy, evidence suggests that clinicians frequently overprescribe antibacterial therapy and underprescribe antiviral therapy for patients with influenza infection. Furthermore, there is often significant delay in prescribing antiviral therapy, suggesting that clinicians may not fully appreciate the potential benefit of early antiviral therapy. Among hospitalized adults, evidence suggests that use of antiviral therapy is suboptimal: 51%– 57% of influenza-infected adults in the prepandemic era and 75% and 82% of influenza-infected adults during the first and second waves, respectively, of the 2009 influenza A(H1N1) pandemic were prescribed antiviral therapy during their hospitalization [18]. Less than half of the treated patients had therapy initiated within 48 hours of admission, even during the pandemic [18]. Not surprisingly, 73%–79% of patients received antibacterial therapy, with 93%–95% of these treatment courses initiated within the first 48 hours of admission [18–20]. In this issue of Clinical Infectious Diseases, Havers and colleagues utilize data from patients seen at 5 US Influenza Vaccine Effectiveness Network sites to assess the use of neuraminidase inhibitor and antibacterial therapy in patients with proven influenza [21]. The study collected key demographic and symptom details among adult and pediatric patients with acute respiratory infections who presented to clinics affiliated with a US Influenza Received 23 May 2014; accepted 26 May 2014. Correspondence: Michael G. Ison, MD, MS, Northwestern University Feinberg School of Medicine, Division of Infectious Diseases, 645 N Michigan Ave, Ste 900, Chicago, IL 60611 (mgison@northwestern.edu). Clinical Infectious Diseases © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. DOI: 10.1093/cid/ciu425