'Cool stuff'

The conference hopes to raise funds to save the lives of about four million children worldwide by 2015 How UK overseas aid will be spentWhere does the UK's aid money go?Bill Gates: 'We can wipe out malaria' Political leaders are set to meet to discuss how to ensure children in the world's poorest countries receive vaccinations.

On the eve of the London summit, one of the world's most influential men explained what he hoped would emerge from the global conference.

The process of developing vaccinations is "cool stuff". In fact, "it's as good as writing computer code".

These aren't the musings of a bedroom computer programmer with a passing interest in immunology.

The observations were made by Microsoft founder and philanthropist Bill Gates and they neatly encapsulate his enthusiasm for a campaign to ensure children around the world are protected against potentially fatal diseases.

With his head cocked to one side and a broad smile on his face, his voice fizzed with passion when he described the "magic" of vaccines.

"They're very inexpensive, they can protect you for your entire life, so diseases like smallpox that used to kill millions are completely gone because of the vaccine. It's the greatest thing that ever happened in human health.

"We need to get them out to people and invent some more."