Using antiviral agents to control outbreaks of influenza A infection.

Risk of influenza mortality is high among older Americans and especially so among those residing in nursing homes. Current recommendations call for annual vaccination of all nursing home residents and staff against type A influenza, but outbreaks can and do occur even in homes with high vaccination rates. If an outbreak occurs, all residents--whether ill or not--should receive an antiviral drug, and prophylaxis should be initiated regardless of residents' vaccination status. The antiviral agents rimantadine and amantadine are both effective for prophylaxis and treatment of type A influenza, but rimantadine appears to cause fewer CNS side effects.