The World Health Organization predicts that swine flu will spread so fast in the coming months it will seem to be a worldwide explosion of cases.

WHO officials said the flu pandemic could infect nearly 2 billion people within the next two years. That is nearly one-third of the world's population.

"At a certain point, there will seem to be an explosion in case numbers," WHO's Western Pacific director Shin Young-soo told a symposium of health officials and experts in Beijing. "It is certain there will be more cases and more deaths."

Health officials are looking into ways to speed up production of the swine flu vaccine.

They said it should be available as early as September.

So far, 1,800 people worldwide have died from the swine flu.

*Originally published August 22, 2009