Mr Bill Gates is donating $100 million to help immunise children in developing countries against a handful of leading childhood diseases.

The gift, which is being given by the Microsoft chairman with his wife, Melinda, through the William H. Gates Foundation, is designed to accelerate access in developing countries to new vaccines that protect US children against meningitis as well as respiratory and diarrhoeal illnesses.

"We have a social imperative to work together to address this basic inequity," Mr Gates said in an interview. "New life-saving vaccines quickly become available to children in the developed world, but recent history shows us that children in the developing world have to wait up to 15 years for the same vaccine."

The $100 million grant won't pay for the vaccines, but will lay the foundation for administering them.