August 21, 2006

WHO urges vaccine developers to update bird flu strains
 

The World Health Organization Friday (Aug 18) urged drug manufacturers to base their vaccine research on new strains of the bird flu virus to keep track of their rapidly evolving status.

Worldwide, there are about a dozen companies trying to produce vaccines based on viruses obtained from Vietnam during its outbreak in 2004.

Dr. Keiji Fukuda, coordinator of WHO's Global Influenza Programme, said the strains being used should match the speed of the virus' evolution.

The disease has branched into two distinct genetic families or clades since 2003. The Vietnam 2004 strain belongs to the first clade while the second clade emerged in China, Indonesia, the Middle East, Europe, and Africa in 2005.

WHO said additional strains from this second clade should be added to the strains under research in the companies' efforts to come up with a vaccine.

That means vaccine developers would have to continue to play catch-up with the virus as it evolves. For developers, it is essentially a guessing-game of which virus strain would pose enough of a threat to be worth the time and effort to invest in.

In the process, researchers would gain more knowledge about the virus and the  vaccines required to stop it, Fukuda said.

However, such talk has unnerved the vaccine market as countries such as the US have stockpiled millions of doses of bird flu vaccines which may have become obsolete as they are made based on the older Vietnam strains.

Even so, a vaccine developed for one particular strain would most likely offer some form of protection or another, according to Dr. Nancy Cox, director of the influenza division at the US Centres for Disease Control and Prevention.

Even though a lot still remains to be discovered, it does not mean that the investment into a vaccine has been wasted, Cox added. The knowledge gained about the process of designing and testing the vaccine would be valuable experience towards making the next vaccine, she said.