Pandemic Preparedness
- WHO statement
on modelling papers published in Science and Nature 4 August 2005
- WHO global influenza preparedness plan (2005)
- WHO checklist for influenza pandemic preparedness planning
- Strengthening
pandemic influenza preparedness and response Report by the Secretariat, World Health Assembly, 2005
- Influenza pandemic preparedness and response, Report by the Secretariat to the
WHO Executive Board, January 2005
- Informal consultation on influenza pandemic preparedness in countries with
limited resources
- WHO Guidelines on the Use of Vaccines and Antivirals during Influenza Pandemics
- WHO
consultation on priority public health interventions before and during an
influenza pandemic
- National
Influenza Pandemic Plans
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.
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