1. PANDEMIC INFLUENZA IS DIFFERENT FROM AVIAN INFLUENZA
Avian influenza refers to a large group of different influenza viruses that primarily affect birds. An influenza pandemic happens when a new subtype emerges that has not previously circulated in humans. Avian H5N1 is a strain with pandemic potential.
2. INFLUENZA PANDEMICS ARE RECURRING EVENTS
An influenza pandemic is a rare but recurrent event. Three pandemics occurred in the previous century: 'Spanish influenza' in 1918, 'Asian influenza' in 1957, and 'Hong Kong influenza' in 1968. The 1918 pandemic killed an estimated 40-50 million people worldwide.
3. THE WORLD MAY BE ON THE BRINK OF ANOTHER PANDEMIC
Health experts have been monitoring a new and extremely severe influenza virus - the H5N1 strain - for almost eight years. The H5N1 strain first infected humans in Hong Kong in 1997, and since mid-2003 this virus has caused the largest and most severe outbreaks in poultry on record. Should H5N1 evolve to a form as contagious as normal influenza, a pandemic could begin.
4. ALL COUNTRIES WILL BE AFFECTED
Once a fully contagious virus emerges, its global spread is considered inevitable. Countries might, through measures such as border closures and travel restrictions, delay arrival of the virus, but cannot stop it. Given the speed and volume of international air travel today, the virus could spread more rapidly, possibly reaching all continents in less than three months.
5. WIDESPREAD ILLNESS WILL OCCUR
Because most people will have no immunity to the pandemic virus, infection and illness rates are expected to be higher than during seasonal epidemics of normal influenza. Current projections for the next pandemic estimate that a substantial percentage of the world's population will require some form of medical care.
6. MEDICAL SUPPLIES WILL BE INADEQUATE
Supplies of vaccines and antiviral drugs - the two most important medical interventions for reducing illness and deaths during a pandemic - will be inadequate in all countries at the start of a pandemic and for many months thereafter. On present trends, many developing countries will have no access to vaccines for the duration of a pandemic.
7. LARGE NUMBERS OF DEATHS WILL OCCUR
Historically, the number of deaths during a pandemic has varied greatly. Death rates are largely determined by four factors: the number of people who become infected, the virulence of the virus, the underlying characteristics and vulnerability of affected populations, and the effectiveness of preventive measures. WHO has used a relatively conservative estimate - from two million to 7.4 million deaths.
8. ECONOMIC AND SOCIAL DISRUPTION WILL BE GREAT
High rates of illness and worker absenteeism are expected, and these will contribute to social and economic disruption.
9. EVERY COUNTRY MUST BE PREPARED
WHO has issued a series of recommended strategic actions for responding to the influenza pandemic threat and to provide different layers of defence.
10. WHO WILL ALERT THE WORLD WHEN THE PANDEMIC THREAT INCREASES
WHO works closely with countries and ministries of health.
Source: World Health Organisation, www.who.int.
