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Pandemic preparedness
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WHO Influenza Pandemic Task Force. report of the first meeting
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WHO global influenza preparedness plan (2005)
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WHO checklist for influenza pandemic preparedness planning
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National Influenza Pandemic Plans
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Considerations on exercises to validate pandemic preparedness plans [pdf 30kb]
An influenza pandemic
An influenza pandemic occurs when a new influenza virus appears against
which the human population has no immunity, resulting in several,
simultaneous epidemics worldwide with enormous numbers of deaths and
illness. With the increase in global transport and communications, as
well as urbanization and overcrowded conditions, epidemics due the new
influenza virus are likely to quickly take hold around the world.
A new influenza virus: how it could cause a pandemic
Annual outbreaks of influenza are due to minor changes in the surface
proteins of the viruses that enable the viruses to evade the immunity
humans have developed after previous infections with the viruses or in
response to vaccinations. When a major change in either one or both of
their surface proteins occurs spontaneously, no one will have partial
or full immunity against infection because it is a completely new
virus. If this new virus also has the capacity to spread from
person-to-person, then a pandemic will occur.
Outbreaks of influenza in animals,
especially when happening simultaneously with annual outbreaks 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 just a matter of time.
Consequences of an influenza pandemic
In the past, new strains have generated pandemics causing high death
rates and great social disruption. In the 20th century, the greatest
influenza pandemic occurred in 1918 -1919 and caused an estimated 40–50
million deaths world wide.
Although health care has improved in the last decades, epidemiological
models from the Centers for Disease Control and Prevention, Atlanta,
USA project that today a pandemic is likely to result in 2 to 7.4
million deaths globally. In high income countries alone, accounting for
15% of the worlds population, models project a demand for 134–233
million outpatient visits and 1.5–5.2 million hospital admissions.
However, the impact of the next pandemic is likely to be the greatest
in low income countries because of different population characteristics
and the already strained health care resources.
If an influenza pandemic appears, we could expect the following:
- Given the high level of global traffic, the pandemic virus may spread rapidly, leaving little or no time to prepare.
- Vaccines,
antiviral agents and antibiotics to treat secondary infections will be
in short supply and will be unequally distributed. It will take several
months before any vaccine becomes available.
- Medical facilities will be overwhelmed.
- Widespread
illness may result in sudden and potentially significant shortages of
personnel to provide essential community services.
- The
effect of influenza on individual communities will be relatively
prolonged when compared to other natural disasters, as it is expected
that outbreaks will reoccur.
Detecting a new pandemic virus
Continuous global surveillance of influenza is key. WHO has a network
of 112 National Influenza Centres that monitors influenza activity and
isolates influenza viruses in all continents. National Influenza
Centres will report the emergence of an “unusual” influenza virus
immediately to the WHO Global Influenza Programme or to 1 of the 4 WHO Collaborating Centres.
Rapid detection of unusual influenza outbreaks, isolation of possible
pandemic viruses and immediate alert to the WHO system by national
authorities is decisive for mounting a timely and efficient response to
pandemics.
Preparing for an influenza pandemic
Contingency planning for an event sometime in the future is often
difficult to justify, particularly in the face of limited resources and
more urgent problems and priorities. However, there are two main
reasons to invest in pandemic preparedness:
1. Preparation will mitigate the direct medical and economic effects of
a pandemic, by ensuring that adequate measures will be taken and
implemented before the pandemic occurs.
2. Preparing for the next influenza pandemic will provide benefits now,
as improvements in infrastructure can have immediate and lasting
benefits, and can also mitigate the effect of other epidemics or
infectious disease threats.
A major component of pandemic preparedness is to strengthen
the capacity to respond to yearly epidemics of influenza. A
surveillance network for human and animal influenza and a targeted
influenza vaccination programme are the cornerstones of a national
influenza policy.
Ensuring an adequate system for alert, response and disaster
management, should be the basis of every national pandemic preparedness
plan. Depending on the available resources, more specific preparations
can be made, such as developing specific contingency plans, stockpiling
of antivirals, strengthening risk communications, investing in pandemic
vaccine research and promoting domestic production of influenza
vaccines.
WHO has developed a global influenza preparedness plan,
which defines the responsibilities of WHO and national authorities in
case of an influenza pandemic. This plan incorporates new scientific
data and experience obtained during recent outbreaks that had pandemic
potential. WHO also offers guidance tools and training to assist in the
development of national pandemic preparedness plans.
More information
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WHO statement on modelling papers published in Science and Nature 4 August 2005
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Strengthening pandemic influenza preparedness and response Report by the Secretariat, World Health Assembly, 2005
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Influenza pandemic preparedness and response, Report by the Secretariat to the WHO Executive Board, January 2005
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Informal consultation on influenza pandemic preparedness in countries with limited resources
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WHO Guidelines on the Use of Vaccines and Antivirals during Influenza Pandemics
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WHO consultation on priority public health interventions before and during an influenza pandemic
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