Officials from 80 countries gathered in Washington on Friday to come up with plans to fight the threat of a global outbreak of avian influenza or bird flu. President Bush urged pharmaceutical executives to focus on influenza vaccines. It's the latest in a series of preparations for a possible pandemic after criticism of the government's response to Hurricane Katrina. Experts have been warning since 2003 that bird flu is the biggest current health threat to the world but policy efforts to battle it have increased in recent weeks.

The virus has killed millions of birds across Asia and infected more than 100 people, killing more than 60 of them in four Asian countries. Manufacturing a vaccine for bird flu would involve the same methods used for a vaccine against regular flu. But experts say the country's flu vaccine system is now so weak that if there were a bird flu outbreak, a vaccine would not be an option. Following last year's flu vaccine shortage, Congress and health agencies are working to find ways to lure drug companies back into the business of making it.

Health and Human Services Secretary Mike Leavitt told the foreign health officials that preventing a pandemic would require a network of countries working together. And he said though a pandemic may be avoided this year, or next year, there eventually will be one, as there was in 1918, 1957 and 1968.