Swine flu and the 'if... factor'

Like everyone we've been watching hour-by-hour as the swine flu situation changes, as new cases are confirmed and the WHO delivers the sort of warnings usually seen at the beginning of a disaster movie.

The problem is, as Oxford's Angela McLean explains in this excellent article in The Daily Telegraph, whilst the risks are all too real we simply don't know how this real-life movie will pan out or whether we are heading for disaster, for a rather-worse-than-usual flu season, or for something in between.

Angela writes: 'This uncertainty is the main problem – and why it is utterly impossible to make confident predictions about what will happen next, or how many cases we can expect.'

'Influenza is notorious for its ability to mutate. The good news is that the British flu season has passed, so there is a very real possibility that we will see very limited transmission in the UK for many months.'

'This is what happened in the most recent pandemic, in 1968: that strain of the disease arose in south-east Asia in July, but no epidemic in the UK until December. Although it was unusually long-lasting, with high numbers of cases occurring into mid-April, the 1969 epidemic was never particularly intense. There was no great excess in mortality: indeed, I was a schoolchild in London and have no memory of the pandemic at all.'

She says that so far the UK Government is doing the right things, using anti-viral drugs in a targeted way to try and contain the outbreak. But, of course, the real test is likely to come if large numbers of people become infected demanding treatment at the same time or previously unknown reservoirs of the disease are suddenly discovered.

Up to this point media reporting of the possible pandemic has been reasonably accurate and appropriate to the very serious threat a virulent flu outbreak poses. But, as time goes on, this 'if.. factor' inevitably becomes a problem for reporters who want solid facts and definite opinions: at the moment most scientists don't have either and need to analyse both the virus and the pattern of the outbreak before they can say more.

As Ben Goldacre notes in The Guardian the backlash against the gloomiest predictions has already begun as journalists begin to worry that perhaps they have over-hyped what is an extremely difficult story to get to grips with.

At the moment we have more questions than answers and we're being told to do little more than take basic hygiene precautions, which is a pretty uncomfortable place to be: everyone wants to know 'yes, but will it be like the last pandemic in 1968? or more like the 1957 one? and what about the terrible 1918 flu?...'

We may not be able to answer these questions yet but Angela closes her article by telling us to remember that all these 'ifs' mean that, like some past pandemics, this one may not be the disaster we all fear:

'The only good pandemic is a pandemic that is over. Since that is not on offer, the next best thing is a pandemic that causes a mild disease and has a very low fatality rate.'

'We have seen from the past 10 days that things can change fast, but for now it is still possible to hope that if a pandemic does emerge, it will be mild enough that today's schoolchildren will scarcely remember it come the great panic of 2049.'

Professor Angela McLean is co-director of the Institute for Emerging Infections at Oxford University and is based at Oxford's Department of Zoology.