Neuraminidase inhibitors for treatment of influenza A and B infections.

Influenza epidemics are responsible for an average of approximately 20,000 deaths per year in the United States. The main method for preventing influenza and its severe complications is influenza vaccination. Influenza-specific antiviral drugs are an important adjunct to vaccine but are not a substitute for vaccine. In the United States, four antiviral agents are approved for preventing or treating influenza: amantadine, rimantadine, zanamivir, and oseltamivir. Amantadine was approved for prophylaxis of influenza A(H2N2) infection in the United States in 1966 and was approved for prophylaxis and treatment of influenza A infection in 1976; rimantadine was approved for treatment and prophylaxis of influenza A infection in 1993 [corrected]. This report provides information on two neuraminidase inhibitors, zanamivir and oseltamivir, which were approved in 1999. Neuraminidase inhibitors are a new class of antiviral drugs that inhibit influenza A and B viruses. Zanamivir is approved for treatment of uncomplicated acute illness caused by influenza virus in persons aged > or =12 years who have been symptomatic for no more than 2 days. Oseltamivir is approved for treatment of uncomplicated illness caused by influenza infection in adults aged > or =18 years who have been symptomatic for no more than 2 days. Neither zanamivir nor oseltamivir is approved for influenza prophylaxis. This report and the Advisory Committee on Immunization Practices (ACIP) 1999 recommendations on influenza prevention and control (MMWR 1999;48[No.RR-4]:1-28) can be accessed at the website for the Influenza Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC, at or at the MMWR website at .