Measures for control of influenza.

Influenza viruses cause recurring illnesses among individuals and recurring epidemics among populations. The major effective control measure for preventing infection and illness is inactivated vaccine, which can prevent influenza illnesses and their complications when given before exposure to the virus. While inactivated vaccine is effective for preventing influenza in most individuals, recommendations for its use focus on the prevention of severe disease and death among those who are at high risk of complications. Live attenuated cold-adapted influenza vaccines are nearing availability. They are given by nasal spray and are particularly effective for preventing influenza among young children, but also for preventing influenza among young adults, and enhancing protection against influenza when given with inactivated vaccine to elderly persons. The antiviral agents amantadine and rimantadine are related compounds that are effective for the prevention and treatment of influenza A virus infections and illnesses. Disadvantages are the rapid development of resistance during treatment and CNS adverse effects with amantadine. These drugs are also effective for outbreak control. Ribavirin is an antiviral given by small particle aerosol that is approved for the treatment of respiratory syncytial virus disease; it is also effective for the treatment of influenza. Two new antiviral agents inhibit influenza viral neuraminidase activity; one is given by inhalation or intranasally (zanamivir) and the other orally (GS4104). The former is free of adverse effects, while the latter induces nausea and vomiting in some individuals. Both are effective for the prevention as well as the treatment of influenza A and B illnesses. Thus, various measures for preventing and treating influenza are nearing availability. Their optimal use should further improve the control of influenza in individuals and populations as well as permit efforts to prevent community epidemics.