Don't panic - just yet

SCMP October 31 2005


Are we in danger of talking ourselves into a crisis over avian flu? If our experience of Sars is any guide, we need to be on constant alert. But having been at the epicentre of severe acute respiratory syndrome, we should also remember the huge economic damage done by fear to countries that had only a few cases, if any. Indeed, we may also remember how visitors from Hong Kong were shunned or even barred.

Any action by way of quarantines, whether local or international, must be judged on two grounds. First, is it a practical method of trying to prevent the spread of disease, or simply a bold-sounding measure by governments which need to be seen to be 'doing something'.

Second, there has to be some assessment, difficult though that is, of the economic cost to the vast majority by minimising the risk to a minority who might be in danger from a high-mortality virus. In health, as in other aspects of society, trade-offs are inevitable.

This dilemma is not new. Indeed, one of the first written discussions of it was penned by none other than one of Hong Kong's early colonial governors, John Bowring - a distant forebear. Bowring was no medical expert, but was a widely travelled man of great learning, who had a keen understanding both of statistics and the processes of government.

In 1838, he delivered a paper to the British Association of Science, entitled Observations on the Oriental plague and on quarantines as a means of arresting it. It was the result of a lengthy visit to Turkey and Egypt. Plague epidemics occurred sporadically throughout the southern and eastern Mediterranean, and quarantines of whole cities - such as Alexandria in 1834 - were the usual official response. The 1834 epidemic killed some 200,000 (or 5 per cent of the population) in Egypt.

Bowring quoted a Scottish doctor resident in Alexandria that quarantines were due to 'superstition and ignorance'. He concluded that plague was endemic, and epidemics were localised and closely associated with weather patterns. The disease could be spread by birds and animals, so quarantining humans was pointless. Mortality rates from plague were largely a function of living conditions - overcrowding and a lack of ventilation. Quarantines were, anyway, almost impossible to enforce. Support for them, he concluded, came largely from those with an official or pecuniary interest. Right or wrong, Bowring's observations are an interesting insight into an old problem.

So what should we do? Clearly, arming ourselves with Tamiflu is sensible. Better public hygiene is a good idea. And tracking and isolating disease outbreaks among birds is wise.

But closing borders? That sounds suspiciously like the quack 19th-century solution. As of now, the disease is not spreading between humans - but public (and stock market) sentiment is imagining the worst. And if it does become transmissible in this way, there are other questions to ask before we panic. If it spreads easily, quarantine solutions are irrelevant. If, like Sars, its spread is not so easy, quarantine may be useless because transmission may precede the symptoms.

And while the virus can mutate to become more dangerous and transmissible, it can also do the opposite, as appears to have happened to Sars. According to one expert, the risk to Hong Kong is 'extremely small', many times less, in fact, than the risk of injury or death when driving on our roads.

I do not envy the health officials who must make judgments about risk. But, as other diseases ranging from dengue to encephalitis to the pig-borne infection show, the world is replete with dangerous viruses. Pandemics are rare and their nature is unpredictable.

But until the threat of H5N1 moves from being a disease that kills a few hundred worldwide to one spreading to tens and hundreds of thousands, we should try to keep it in context.



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