Planning for the next pandemic of influenza.

Worldwide influenza pandemics have occurred at irregular and unpredictable intervals throughout history and it is confidently expected that they will continue to occur in the future. It is now recognised that these pandemics result when avian influenza A viruses succeed in adaptation to and transmission between humans. The impact of pandemic influenza is substantial in terms of morbidity, mortality and economic cost and there is the potential for serious social disruption. Influenza vaccines remain the most effective defence against influenza but will be in short supply during a pandemic, as will the new specific anti-influenza drugs, due to the lead-time required for production and rapid spread of the virus. To minimise the impact of pandemics it is imperative to maximise the availability of both vaccines and antivirals and to ensure that they are used optimally. This requires planning at both the international and national levels. The World Health Organization has, therefore, developed a staged plan for responding to a pandemic threat which is based principally on its surveillance program. It has also prepared guidelines to assist national agencies in their planning. However, there may be further options for increasing our preparedness which should also be considered.