An influenza pandemic occurs when a new influenza virus capable of causing severe disease transmits easily among humans. Since there is no immunity to a newly emerging virus in the human population, it can cause a pandemic – an epidemic on a global scale. With the continuing spread of the avian influenza A(H5N1) virus in poultry and wild birds, as well as the increasing number of human infections, there is a growing risk of an influenza pandemic in humans.

While it is impossible to predict with accuracy when a pandemic might occur or its exact impact, the potential for widespread human infection – accompanied by severe illness and death – cannot be dismissed. An avian influenza pandemic also would cause catastrophic social and economic disruption. In fact, a pandemic is more than a health crisis; it is a challenge that must be met by all sectors of society.

Preparation can mitigate the direct health, social and economic impacts of a pandemic. WHO recommends that each country and area have in place a pandemic preparedness plan. The planning process should involve a broad spectrum of government ministries and agencies, as well as civil society. WHO has the responsibility to assist its Member States in developing their preparedness plans.