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DAWN OF THE FRANKENSTEIN KILLER FLU
The Mail on Sunday, 19 September 2004

FLU BIGGER THREAT TO US THAN TERRORISM
The Sun, 23 August 2004

NEW STRAIN OF FLU COULD KILL MILLIONS AROUND THE WORLD
The Independent, 28 August 2004

BRITONS AT RISK FROM A JET-SET FLU EPIDEMIC
Daily Mail, 1 October 2004

Headlines like these can be alarming. While they draw attention to a very real threat, they also leave many questions unanswered: What is pandemic flu? Why are we at risk now? What is the difference between pandemic flu and 'ordinary' flu? How can 'bird flu' lead to pandemic flu? How likely is a flu pandemic? What treatments are available? How would it affect the UK? How would it affect me? And, most importantly, how do we control it? Understanding the nature of pandemic flu is an important part of being prepared.

Flu pandemics are global epidemics of a newly emerged strain of flu to which most people have little or no immunity. Much of our understanding of pandemic flu comes from the experience of three major flu pandemics last century, the first and worst of which killed an estimated 20-40 million people worldwide - more lives lost than during the First World War. As history has shown, pandemic flu differs from 'ordinary' flu in important ways. For example, 'ordinary' flu occurs seasonally, allowing us time to identify the virus and administer a vaccine in advance, whereas pandemic flu can occur at any time allowing no time for a vaccine to be prepared because the virus is completely new. Ordinary flu most seriously affects the elderly and vulnerable groups while pandemic flu can affect people of any age. These differences strongly influence the way in which we respond to pandemic flu.

Immunisation - having the flu 'jab' - is the principal countermeasure in protecting people from influenza. However, a vaccine for pandemic flu is unlikely to be available in the early stages of the pandemic since its development can only begin once the virus has been identified. Antiviral drugs, the second major tool in pandemic flu control, are likely to be effective in reducing the seriousness of the illness. However, it is impossible to measure their efficacy until the virus is circulating and there is some concern that the virus could develop resistance. Antivirals are also costly and have a limited shelf life of five years.

Why should we worry about avian (bird) flu? Evidence suggests that recent pandemic flu viruses originated in birds. During the last few years, the world has faced several threats with pandemic potential - principally from outbreaks of avian flu. Many experts believe that the outbreak of highly pathogenic avian flu (A/H5N1) in Hong Kong in 1997 in which 18 people were infected, six of whom died, could have led to a pandemic, if it wasn't for the prompt destruction of Hong Kong's entire poultry population - almost 1.5 million chickens . The current outbreak of highly pathogenic avian flu (A/H5N1) which has affected poultry in numerous countries in Asia, and has to date infected 55 people, of whom 42 have died, has brought the threat of pandemic flu close again.

While it is unlikely that a pandemic flu virus will originate in the UK, no country is exempt from risk. Once a pandemic virus emerges, we will probably not be able to prevent its global spread; but by being prepared we can significantly reduce its impact. How severe the next pandemic will be, who will be most at risk and how many people will be affected cannot be predicted with any certainty. The scale and severity of illness associated with previous pandemics have varied; we can assume, however, that they will be of greater magnitude than even the most severe epidemic of 'ordinary' flu. Experts predict anything between 2 million and 50 million deaths globally. From a variety of possible outcomes, the UK plan assumes that around a quarter of the population will be affected with over 50,000 deaths. The uncertainty over precisely how a flu pandemic will affect the UK, and indeed any other country, poses a significant challenge to our preparatory efforts. The UK plan is, therefore, a flexible document and will be continually updated as more information emerges.

What we do know is that pandemic viruses spread rapidly. During the pandemics of 1957 and 1968, the viruses took only three to four months to spread from south-east Asia - where they were first identified - to Europe and North America. The intercontinental spread of Severe Acute Respiratory Syndrome (SARS) in 2003 was even faster. Within four months of the global alert, more than 8000 people had been affected in 30 countries across six continents and 900 people had died. The expansion of international air travel is likely to make the spread of pandemic flu just as rapid. All these experiences indicate that once a pandemic flu strain has been identified as causing illness in one country, it will be too late to begin planning.

The old adage, 'forewarned is forearmed', has particular resonance as we face this potential risk to global public health. The timing and the precise impact of another flu pandemic may not be clear but by preparing for every eventuality now, before it occurs, we stand the best chance of reducing its impact. Even with good planning and preparation though, the consequences of pandemic flu would still be very serious.