The Bill and Melinda Gates Foundation awarded US$255 million to Rotary International, which will match it with US$100 million to be raised over the next three years. At the same time the British and German governments awarded £100 million (US$137 million) and €100 million (US$129 million) respectively to bring the total committed by the four parties to US$630 million.

"We know exactly how many children got polio last year: 1,625," said Gates, who was speaking in a televised speech at Rotary International's international assembly in San Diego. "Compared to the numbers from 20 years ago that's not very much. Some may be tempted to think 'well, isn't that good enough' but there is no such thing as containing polio at its current levels."

"The mathematics of polio are clear, we cannot maintain the level of one or two thousand cases per year. Either we eradicate it or it returns to the days of tens or even hundreds of thousands of cases per year," he said.

The grant follows a US$100 million pledge made a year ago by Gates' foundation to Rotary International, which the organization also committed to matching with the same amount of money.

Since stepping down from day-to-day control of Microsoft, Bill Gates has devoted more of his time to the that is named for him and his wife. Several main areas are targeted by the foundation's grants, including global health care, of which polio is a part. The health care work also includes HIV/AIDS, malaria, pneumonia and maternal and child health care.