Neuraminidase inhibitors for influenza.

N Engl J Med 2005;353:1363-73. Copyright © 2005 Massachusetts Medical Society. he impact of influenza infection is felt globally each year when the disease develops in approximately 20 percent of the world’s population. In the United States, influenza infections occur in epidemics each winter, generally between late December and early March. Recent events, including human cases of avian influenza, have heightened awareness of the threat of a pandemic and have spurred efforts to develop plans for its control. Although vaccination is the primary strategy for the prevention of influenza, there are a number of likely scenarios for which vaccination is inadequate and effective antiviral agents would be of the utmost importance. During any influenza season, antigenic drift in the virus may occur after formulation of the year’s vaccine has taken place, rendering the vaccine less protective, and outbreaks can more easily occur among highrisk populations. In the course of a pandemic, vaccine supplies would be inadequate. Vaccine production by current methods cannot be carried out with the speed required to halt the progress of a new strain of influenza virus; therefore, it is likely that vaccine would not be available for the first wave of spread of virus. 1 Antiviral agents thus form an important part of a rational approach to epidemic influenza and are critical to planning for a pandemic.