WHO Chief Expects Swine Flu Will Mutate GENEVA, SWITZERLAND (Associated Press) -

The WHO's flu chief says the swine flu will likely mutate over a long period of time as it spreads across the globe. And Keiji Fukuda says its impossible to predict what shape the virus may take.

With hundreds of thousands of swine flu cases estimated worldwide, the World Health Organization says the first vaccines may not be ready until October. Fukuda says the virus hasn't yet shown a widespread resistance to the anti-viral drug Tamiflu, although a few scattered cases have developed.

Rich nations have already have already pre-ordered most of the vaccine's available stock. But, the WHO says two drug makers have pledged to donate 150 million doses of vaccine to poorer countries by the end of October.

Fukuda says the pandemic is in its early stages and the virus is likely to seep deeper into the population for some time.

The WHO says some 800 people have died from the bug worldwide. © Copyright 2012, Associated Press