The World Health Organisation has issued a stark warning on the possibility of a global flu pandemic, which would probably kill over -7 million- (2004-11-30: see below) people world wide.
The breakout could occur any time from the next few weeks to several years from now, but unless there is close cooperation between nations around the world, containment of the virus will be impossible. The reason for concern is the fear that the asian bird flu virus may have recently infected humans for the first time, in Asia. A human vaccine for the bird flu virus is not expected until March 2005 at the earliest.
The worst recent outbreak of a new flu strain is the Spanish flu in 1918-19, when up to 50 million people are thought to have died – nearly half of them young, healthy adults.
Update (2004-11-30): I thought the figure of 7 million sounded low, the WHO has just been quoted as saying that the upper range is a lot higher – over 50 to 100 million could die when bird flu breaks out. The 7 million is, as stated in the original article, a low end-of-the-range figure.