The threat and prospects for control of an influenza pandemic.

Influenza constitutes the most widespread and significant respiratory infectious disease in the world, resulting in increased morbidity, mortality and economic loss each epidemic year. Pandemic influenza is a worldwide epidemic usually caused by a new virus variant to which the majority of the population has no immunity. As demonstrated in the devastating pandemic of 1918 to 1919, a pandemic virus may infect 30 to 50% of the worlds population and kill 1 to 2% of those infected. Pandemic control must be a concerted and co-ordinated world strategy and under the auspices of the World Health Organization, pandemic preparedness plans have been formulated, including: intensified surveillance for more rapid identification of new reassortant viruses with potential human virulence and infectivity, laboratory characterization of the new viruses so that vaccine may be prepared, development of techniques for more rapid vaccine production and the manufacture and stock piling of antiviral drugs. The H5N1 outbreak of virulent chicken influenza in 1997 in Hong Kong which resulted in the deaths of six of 18 infected persons serves as a wake-up call. Should such a virus attain high transmissibility in humans, a pandemic of tragic proportions might ensue. Even though the timing of onset of the next pandemic cannot be precisely predicted, world governments must understand the urgency of the problem and increase funding for influenza pandemic control.