Scientists have offered a decent explanation for why the bird flu pandemic we're all supposed to be cowering in our hermetically-sealed Anderson shelters from has yet to materialise.

The H5N1 influenza virus needs to acquire the ability to pass from human to human in order to precipitate the downfall of civilisation. According to virologists reporting in tomorrow's edition of Nature it all comes down to human anatomy.

They say that the disease can only replicate in the presence of a particular flavour of the molecule it recognises and binds to in order to cause trouble. In humans it seems this receptor is concentrated in the lower region of the lungs, which means viruses can only replicate down there. In turn this means it is much less likely to be spread by sick people coughing and sneezing.

The upper respiratory tract has an alternative form of the binding molecule. H5N1 would have to mutate in order to use this molecule.

Given the mainstream media firestorm over bird flu has abated slightly, actual science like this explaining why so far we're not all rotting in mass graves, surrounded by empty packets of Lempsip Max Strength, is unlikely to get much coverage.®