The UK government is an important "change agent" to keep Africa on the international agenda, according to Microsoft boss Bill Gates.
Bill and Melinda Gates used $30bn to set up their foundation
Tony Blair and Gordon Brown had managed to get the continent's plight on the agenda of world leaders, he said.
Gavi, an aid organisation sponsored by Mr Gates, announced on Friday that its vaccination programme had so far saved the lives of 2.3m children in Africa.
Mr Gates told the BBC this proved that aid programmes could deliver success.
Not everything had gone well, he admitted, but overall the programme had met its targets.
Climate change v Africa
Speaking at the sidelines of the World Economic Forum in Davos, Mr Gates and his wife Melinda said Gavi - which has committed $2.6bn (£1.3bn) to support immunisation programmes in 70 developing countries - had only made an impact because governments had supported the cause.
Mr Gates said Africa had failed to follow Asia's path of rapid economic development because it had a different spread of diseases, geography and quality of governance.
Asked whether they were worried that the issue of climate change could push the plight of Africa from the agenda, Mr Gates said he believed that the world should be able to keep more than one issue on top of its mind.
Melinda Gates, however, said while Africa was still high on the agenda of the G8 group of industrialised nations, one had to be careful not to let it slip, because it would "take us a long time to help Africa".
Mr Gates is the world's richest man, and he and his wife had contributed about $30bn to set up the Bill and Melinda Gates Foundation which focuses on health and education initiatives.
In June last year the world's second-richest man, Warren Buffett, said he would donate $37bn of his money to be administered by the Gates foundation.