In a letter describing his first year as a full-time philanthropist, Gates said if just 1 percent of the international pledge of $100 billion to be spent in the next decade to mitigate global warming "came from vaccine funding, then 700,000 more children could die from preventable diseases."
Vaccinations have prevented 1 million childhood deaths since 2005, but 9 million children still die each year, including almost 4.5 million who die within a month of their births, The Seattle Times reported Monday.
In his first year away from Microsoft, Gates has been to Italy, Africa, and India, speaking to farmers, financiers and world leaders as head of the world's largest charity, the $34 billion Bill & Melinda Gates Foundation.
While the aim is to fund innovation, the largest share of donations -- $800 million a year -- go to vaccinations for people in poor countries, Gates said.
In a year, he has gotten a better idea of the scope of the world's problems, he said.
"Seeing the work firsthand reminds me of how urgent the needs are as well as how challenging it is to get all the right pieces to come together," he wrote.