Beware the return of swine flu

• 19 May 2009
• Magazine issue 2708. Subscribe and get 4 free issues.

THE backlash was predictable. Around the world, pundits and even some politicians are calling for an end to "crying wolf" over swine flu. It's no worse than ordinary flu, they say, brandishing news reports of mild cases. Why are we wasting money on this nonsense?

Bluster of this kind will be with us as long as it attracts newspaper readers and TV viewers. But let's be clear: nobody who knows the first thing about flu is crying wolf. It is an inherently unpredictable disease, and the fact that the H1N1 virus has not yet wreaked obvious havoc doesn't mean there is no cause for serious concern. Yes, it is possible that the virus will fizzle out completely. Yes, it is possible that if or when it comes back for another go, it will - unlike the last H1N1 pandemic in 1918 - be no more lethal than it is now.

The fact that the H1N1 virus has not yet wreaked obvious havoc doesn't mean there is no cause for concern

If this virus fails to persist, so much the better. But there is a real danger that it will launch another wave - perhaps in as little as a few months - and it makes sense to do everything to prepare for the worst. The appearance of the Mexican virus has exposed our inability to make timely quantities of vaccine (see "'Pandemic' flu vaccine will be too late for most") despite the best efforts of the industry and five years of angst over bird flu - a threat which, incidentally, remains real.

It is also wrong to assert that Mexican H1N1 is little more serious than ordinary flu. Yes, the raw mortality figures make it seem that way. Ordinary flu kills about half a million people a year - about 0.2 to 0.5 per cent of those who catch it. For the Mexican virus the current, early estimate looks only slightly worse: something between 0.3 to 1.5 per cent of people who caught it have died.

But behind these figures there is a crucial difference. Ever since we got antibiotics to defeat the bacterial pneumonia that can follow flu, nearly all deaths from regular flu have been in the elderly, and they are now almost exclusively among the over-75s. It may sound callous, but the truth is that most of those who die of flu have a good chance of dying soon anyway; it just happens to be flu that strikes the final blow.

But in Mexico it has been those aged 15 to 54 who have got really sick with this virus. These are people who would expect to have many productive years ahead of them: the teenage students, the twenty-something parents, the farmers and doctors and truckers who make the world work. Even if this virus gets no worse, the burden of illness and death rates shifted onto this age group would have a very different impact from ordinary flu.

We need to take the new H1N1 flu seriously. And then hope the wolf really does slink away. Either way, we need to make sure we're better prepared next time.