It is clear that avian flu poses a real threat to Western as well as Asian populations, even if the risk of a pandemic is still relatively small. It is also clear that the world’s capacity to respond is woefully inadequate. The Government’s decision to stockpile the anti-viral drug Tamiflu is sensible. But it needs to do much more to build up capacity to manufacture vaccines, should the worst come to the worst.

Growing concern about a pandemic has been accelerated by the discovery that the H5N1 virus, which had previously been caught only from birds, now seems to have spread from person to person in Vietnam. Official figures that bird flu has killed around 45 people in Cambodia, Thailand and Vietnam are thought by many experts to be a significant underestimate.

The World Health Organisation, having previously argued that it is impractical to stockpile vaccines because flu viruses constantly mutate, has changed its stance. It is now recommending that governments build up stocks of a generic vaccine that could prime the immune system so that only a single dose of a strain-specific vaccine would be needed once an outbreak occurred. This would not necessarily prevent people falling ill, but could help to ward off death, particularly since it could take six months to develop a strain-specific vaccine once a pandemic started.

Clinical trials of a generic vaccine are due to start soon in the US, Canada, Australia and Japan. The US Government has ordered four million doses, partly to help the manufacturers to test their production processes. The Italian and French governments have ordered two million doses each. The UK Government’s reluctance to follow suit is beginning to look a little like misplaced penny-pinching. Stockpiled vaccines might never be used. But while Tamiflu is effective against a broad spectrum of flu viruses, it is not a substitute for a generic vaccine.

The growing alarm has exposed the inadequacy of the world’s manufacturing capacity. About 90 million doses of flu vaccine are produced for the EU each year. Even if these factories could transfer all their production to a pandemic vaccine, the supply would be insufficient. In Britain, Chiron, the leading manufacturer, cannot even start production until it solves problems of contamination at its Liverpool factory. And Britain would not have first call on the bulk of EU vaccines: Glaxo ’s main European factory, for example, is in Dresden. Greater production capacity is clearly needed. Since industry is unlikely to invest in vaccines that might never be used, some encouragement from government is needed.

There is some good news in this daunting scenario. While globalisation has undoubtedly accelerated the spread of disease, it also makes it easier to collate information. The world’s response must be proportionate: institutions clearly should not cry “pandemic” too often. But the growing concern at the data coming from Asia suggests that it is worth taking precautions now to boost our future capacity to respond.