Jon Snow interviews Bill and Melinda Gates about their work across the world, follow the interview here.

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The Bill and Melinda Gates Foundation and the Crown Prince of Abu Dhabi have pledged $100 million to deliver vaccines to children in Afghanistan and Pakistan.

Each are donating $50 million to help treat children with five deadly diseases, as well as pneumonia. A third of the funds will be used to get the polio vaccine to as many as 35 million children. Jon Snow interviewed Bill and Melinda Gates, who are at the World Economic Forum in Davos, live earlier today. Follow the blog reaction and watch the video above.

Jon Snow writes on interviewing Bill and Melinda Gates:

Either the richest or second richest man in the world, you don't easily turn down an interview with Bill Gates.

When you manage to secure an interview with both Bill, and Melinda gates, it's clearly quite a moment. Whatever your feelings about wealth and riches, Earth has never seen the scale of philanthropy that the Microsoft founder has amassed and secured for good causes in the developing world.

The interview airs tonight on Channel 4 News and viewers have been tweeting questions for it all day. Bill's reputation is as technology man, and much of his money has been spent on the search for technological answers to disease.

Some have argued he's favoured vaccines over the human factors - more nurses, doctors and community development. But his wife Melinda has compensated to some extent by channelling more recent gates funding into these areas. The Gates Foundation has also been behind a huge GM crop programme in India, which is locally controversial.