BETHESDA, MD 08 September 2009—An updated guidance document from the Centers for Disease Control and Prevention (CDC) asks health care professionals to treat influenza with antivirals only when the patient is at increased risk for flu-related complications.
The document revises recommendations made in May and builds on knowledge gained this past spring in the United States and during the Southern Hemisphere`s flu season, said Anne Schuchat, director of CDC`s National Center for Immunization and Respiratory Disease.
In general, Schuchat said, antiviral treatment recommendations for patients infected with the pandemic H1N1 2009 influenza virus are the same as those for patients infected with seasonal influenza viruses.
"Most people won`t know what type of flu they have," Schuchat told reporters this afternoon. "So our new antiviral guidance really addresses the clinical symptoms of influenza-like illness and suspect[ed] influenza without having to differentiate exactly which strain a person has."
She said hospitalized patients who are believed to have influenza require prompt treatment with antiviral medications. Treatment should begin before definitive laboratory tests confirm the presence of influenza because the benefit is greatest if patients begin treatment within 48 hours after influenza symptoms develop.
People in the community with flu symptoms who have a condition that places them at high risk for influenza-related complications should also receive antiviral treatment, according to CDC. High-risk groups include pregnant women, children under age 5 years and adults 65 or older, and people with respiratory disease, diabetes, and many other chronic medical conditions.
The guidance document places less emphasis on postexposure prophylaxis for high-risk groups by introducing a "watchful waiting" option, Schuchat said.
"Instead of just definitely starting with antiviral medicines, we give providers an option to...wait and see whether fever develops; and when fever develops or respiratory symptoms develop, to give antivirals then," Schuchat said.
She said saving antivirals for treatment use decreases the likelihood that influenza viruses will become resistant to the medications and will ensure that the U.S. supply is sufficient as the flu season progresses.
"We think that the supply of antivirals in the system is adequate for antiviral use for treatment," Schuchat said. "Most people won`t need antiviral medicines to get through the influenza this year."
CDC recommends the use of oseltamivir or zanamivir, the only two FDA-approved neuraminidase inhibitors effective against influenza virus.
Although seasonal strains of H1N1 were universally resistant to oseltamivir during recent flu seasons, Schuchat said the pandemic 2009 H1N1 strain seems to be the only H1N1 strain now circulating.
"We haven`t been seeing the seasonal H1N1 viruses in the Southern Hemisphere, and we don`t know whether they`ll be a problem here in the Northern Hemisphere going through the fall and winter," she said."
For now, Schuchat said, CDC expects oseltamivir and zanamivir to be "great first-line treatment" for influenza.
