CDC advises on antiviral use in flu outbreaks

Dec 18, 2003 (CIDRAP News) – The Centers for Disease Control and Prevention (CDC) yesterday issued guidelines for using antiviral drugs to prevent and treat influenza during the current season.

The guidelines cover the use of four antivirals—oseltamivir, zanamivir, amantadine, and rimantadine. The CDC emphasizes using the medications to control flu outbreaks in nursing homes and other institutions housing people at high risk for flu complications.

The antivirals are estimated to be 70% to 90% effective for preventing flu (chemoprophylaxis) in healthy adults, according to the CDC. When used for treatment within the first 48 hours of illness, they can shorten the time of illness by 1 to 2 days and reduce virus shedding.

Oseltamivir and zanamivir, called neuraminidase inhibitors, reduce the number of viruses released from host cells, the guidelines say. Zanamivir is approved for treatment of flu in people aged 7 and older but not for prevention. Oseltamivir is approved for both treatment (ages 1 and older) and prevention (ages 13 and older).

Amantadine and rimantadine are adamantane derivatives, which inhibit virus replication. Amantadine is approved for treatment and prevention in children (age 1 and older) and adults, while rimantadine is approved for treatment of adults and for prevention in both children and adults.

The guidelines say supplies of the antivirals could run short in some areas. Where shortages occur, people at high risk for flu complications should be first to receive them, the CDC advises. High-risk groups include healthy children aged 6 to 23 months, people aged 65 or older, pregnant women in their second or third trimester, and anyone older than 2 years with a chronic health condition.

Antivirals should be used to control flu outbreaks in institutions and other places that house many high-risk people, including nursing homes, long-term care facilities, hospitals, and cruise ships, according to the guidelines.

The CDC recommends considering using the drugs to treat high-risk people (older than 1 year) who have the flu. Healthcare providers also should consider using the drugs prophylactically to protect unvaccinated high-risk people during community flu outbreaks and in outbreaks in various group settings, the agency says. Preventive use also should be considered for unvaccinated healthcare workers who have close contact with flu patients.

See also:

CDC's interim guidelines on the use of antiviral drugs for chemoprophylaxis and treatment

CDC's background information for clinicians on the use of antiviral drugs

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