Pandemic preparedness

An influenza pandemic

An influenza pandemic occurs when a new influenza virus appears against which the human population has no immunity, resulting in epidemics worldwide with enormous numbers of deaths and illness. With the increase in global transport, as well as urbanization and overcrowded conditions, epidemics due the new influenza virus are likely to quickly take hold around the world.

Outbreaks of influenza in animals, especially when happening simultaneously with annual outbreaks of seasonal influenza in humans, increase the chances of a pandemic, through the merging of animal and human influenza viruses. During the last few years, the world has faced several threats with pandemic potential, making the occurrence of the next pandemic a matter of time.

Consequences of an influenza pandemic

In the past, influenza pandemics have resulted in increased morbidity and mortality and great social disruption. In the 20th century, the most severe influenza pandemic occurred in 1918 -1919 and caused an estimated 40–50 million deaths world wide. Current epidemiological models project that a pandemic could result in 2 to 7.4 million deaths globally.

If an influenza pandemic were to occur today, we could expect:

• the pandemic virus to spread rapidly due to the high level of global traffic;
• vaccines, antiviral agents and antibiotics to treat secondary infections to be in short supply, with a period of several months before any vaccine becomes available;
• medical facilities to be overwhelmed with demands to care for both influenza and non-influenza patients;
• widespread illness to result in sudden and potentially significant shortages of personnel to provide essential community services.

Detecting a new pandemic virus

Continuous global surveillance of influenza is key to the early detection of a virus with pandemic potential. WHO has a network of more than 120 National Influenza Centres in over 90 countries that monitor influenza activity and isolate influenza viruses in every region of the world. National Influenza Centres will report the detection of an “unusual” influenza virus immediately to the WHO Global Influenza Programme and one of the five WHO Collaborating Centres. Rapid detection of unusual influenza outbreaks, isolation of viruses with pandemic potential and immediate alert to WHO by national authorities is critical to a timely and efficient response.

Preparing for an influenza pandemic

Contingency planning for an event that will occur at an undetermined time in the future is difficult, particularly in the face of limited resources and other urgent problems and priorities. However, there are two main reasons to invest in pandemic preparedness

• Improving public health infrastructure through pandemic planning has immediate and lasting benefits, increasing overall response capacity for all threats to public health.
• Strengthening coordination mechanisms at national and international levels contributes to better global preparedness and response for disasters and public health emergencies.

WHO has developed a global influenza preparedness plan, which outlines the responsibilities of WHO and national authorities in the event of an influenza pandemic. WHO also offers guidance tools and training to assist in the development of national pandemic preparedness plans.

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