You've been reading about bird flu, no doubt, and worrying could it happen here? Nurses know how long it takes to manufacture a vaccine, and this knowledge adds to your anxiety. The flu vaccine, for example, takes nine months to manufacture, using a complex process. How then could we get a vaccine for bird flu on short notice?

A recent advance may be the answer. The Centers for Disease Control, and a private company, Fort Dodge Animal Health, an animal biologies and pharmaceutical company, have developed the first licensed DNA vaccine. This particular vaccine works against West Nile virus in horses.

DNA vaccines are made differently from traditional vaccines, which use a weakened or killed micro-organism. Traditional vaccines have a long, and complex manufacturing process. DNA vaccines, in contrast, use selected small pieces of the micro-organism's genetic material to stimulate the vaccine recipient's immune system. This means a DNA vaccine can be manufactured more quickly, and more simply. In addition, DNA vaccines are less subject to temperature fluctuation, and a DNA vaccine can be composed of multiple vaccines against multiple organisms, given in one dose.

The DNA technology used in this horse vaccine has been used to develop a vaccine against West Nile virus in humans. This vaccine is now in early clinical trials in humans.