Editorial: Flu threat remote but care is wise

Seriously, do we need to prepare for bird flu? It is more than two years since the virus appeared in East Asia, where people fell ill from contact with infected poultry, and there is no evidence yet that it has mutated in a way that could spread rapidly through human populations. Now the northern hemisphere is well into winter when people are most susceptible to flu and the virus has appeared in Turkey. There have been 18 confirmed cases and three children have died, bringing the world toll to 150 infected people and at least 78 deaths.

The Turkish victims are the first human cases reported outside East Asia since the virus H5N1 re-emerged in 2003 but the outbreaks remain very localised and attributed to contact with diseased birds. British medical scientists have analysed the viruses from two of the dead Turkish children and found mutations that make it easier for the virus to attach to human cells but they say this is only one step in the process that could turn it into a readily communicable human disease. But the fear remains that the virus will undergo a genetic "shift", which can happen drastically or in a series of small changes, and present a new strain of flu to which nobody has developed immunity.

History has frequently seen new avian flu strains which sweep through populations killing as many as half those infected before the human immune system develops antibodies. There is every reason to assume it will continue to happen from time to time. The question is, does the behaviour so far of this bird flu suggest a new human virus is about to break out? No, say the British scientists who examined the Turkish cases. The genetic change they have observed in the bird flu virus was not enough to make it easily transmissible between humans. "The virus would have to change a lot more in other areas before it could cause a pandemic," said a British Medical Research Council spokesman.

Yet it is tempting to follow the precautionary principle and prepare for the worst. This is certainly the safest course for health authorities who know they will stand condemned if the worst happens and they had failed to ensure the population was prepared. It is also the most profitable course for suppliers of medicine and emergency kits, and indeed for news services who can retail precautionary advice. But there is no future for any of these in exaggerating the threat. Public credibility has already been severely tested in recent years by the "Y2K" computer failure that never happened and the "Sars" virus that did not reach the feared proportions.

This is indeed the danger of the precautionary principle much hallowed by health and environmental agencies today. Every time people go to the trouble of taking precautions for what turns out to be a false alarm, the population develops more immunity to the warnings. So it behoves everyone in control of the alarms to preserve their credibility for the times when danger is imminent.

The danger of a bird flu pandemic remains far from imminent. The precautions that might advisably be taken at this stage are no more drastic than those recommended in case of any natural disaster. Households could keep a sensible stock of durable food and fresh water. Schools and workplaces can seek advice about how to protect people in the event of an outbreak of the virus among them, and how to maintain operations as best they can.

There is much to consider and probably much that can be done. The Herald has begun a daily item of advice that we hope will help people to prepare for the worst if they wish. The advice is offered with the precaution that bird flu is still far from frightening. Preparations will probably turn out to be needless. But it is better to waste the effort now than regret the lack of it later.