Microsoft co-founder Bill Gates pledged 10 billion dollars over the next decade Friday to research and deliver vaccines to the world's poorest countries.
Increased vaccination could save more than eight million children by 2020, said the entrepreneur-turned-philanthropist, announcing the commitment by the Bill and Melinda Gates Foundation he heads with his wife.
But he added that money was needed and called on governments and the private sector to do more.
"We must make this the decade of vaccines," said Gates at the World Economic Forum (WEF) in Davos. "Vaccines already save and improve millions of lives in developing countries.
"Innovation will make it possible to save more children than ever before."
Gates, who is a regular at the annual Swiss ski resort meeting of political and business leaders, called on others to "fill critical financing gaps in both research funding and childhood immunisation programmes."
"Increased investment in vaccines by governments and the private sector could help developing countries dramatically reduce child mortality by the end of the decade," said a Foundation statement.
The projections were based on research by experts at the Johns Hopkins Bloomberg School of Public Health in the United States, on the potential impact of vaccines on childhood deaths over the next 10 years.
By boosting the delivery of vaccines in developing countries to 90 percent coverage, the experts' model suggested that the lives of 7.6 million under-fives could be saved in the next decade.
An additional 1.1 million youngsters could be saved by rapid introduction of a malaria vaccine in 2014, bringing the total lives saved to 8.7 million.
Melinda Gates, who heads the couple's Foundation with her husband, added: "Vaccines are a miracle - with just a few doses, they can prevent deadly diseases for a lifetime.
"We've made vaccines our number-one priority at the Gates Foundation because we've seen firsthand their incredible impact on children's lives," she added at the annual meeting of political and business leaders in the Swiss ski resort.
Commenting on the announcement, WHO chief Margaret Chan said the Gates' commitment was "unprecedented, but just a small part of what is needed.
"It's absolutely crucial that both governments and the private sector step up efforts to provide life-saving vaccines to children who need them most," she added.