IDSA supports neuraminidase inhibitors for flu in specific populations

In the wake of recent systematic reviews critical of anti-flu drugs, the Infectious Diseases Society of America (IDSA) has reaffirmed recommendations on use of neuraminidase inhibitors (NAIs) for treatment of influenza in high-risk patient populations or severe cases.

Two Cochrane systematic reviews on flu relief drugs, which for the first time considered clinical study reports in addition to published studies, concluded that the medicines didn't have much impact on the course of symptoms. The reviews were summarized in last week's ACP InternistWeekly.

In response to the reviews, the IDSA published a statement that continues to recommend the drugs' use in specific populations. For example, IDSA recommends that clinicians start antiviral treatment with oral oseltamivir as soon as possible for any hospitalized patient with suspected or confirmed influenza and for any patient with suspected or confirmed influenza who has severe or progressive illness.

The IDSA statement points out that the Cochrane analysis included both influenza virus-infected and non-infected persons with influenza-like illness. “Given the specific antiviral activity against influenza viruses of NAIs, this analytic approach underestimates NAI treatment efficacy,” the statement said.

The IDSA statement also noted that randomized, controlled trials of NAIs in ambulatory patients with mild illness may not apply to severely ill patients or those at higher risk for influenza complications. Because there are no randomized, controlled trials of NAI treatment of hospitalized patients, evidence from the many observational studies of hospitalized seasonal and pandemic 2009 H1N1 influenza patients should be considered, the society said. These observational studies have consistently reported that NAI treatment of influenza in hospitalized patients reduces severe outcomes, including ICU admission and death, especially when treatment is started within 2 days of illness onset.

Also, the IDSA statement said, no randomized, controlled trial was sufficiently powered to evaluate the effect of oseltamivir treatment of outpatients to reduce influenza-associated complications such as hospitalization or lower respiratory tract infections, which are rare in healthy individuals but more common in people at higher risk for complications. Pooled data from randomized trials have demonstrated a reduction in clinician-diagnosed lower respiratory tract infections requiring antibiotics.

The IDSA also endorses current CDC recommendations, which state that anti-flu medications are an important adjunct to vaccination against the flu.

Clinical trials and observational data show that early antiviral treatment can shorten the duration of fever and illness symptoms and may reduce the risk of complications from influenza, such as otitis media in young children, pneumonia, and respiratory failure; may reduce mortality; and may shorten the duration of hospitalization, according to the CDC.