The online meeting beat a target to raise $7.4 million to provide vaccines at a much reduced cost to 300 million children worldwide over the next five years.
More than 50 countries took part as well as individuals such as billionaire philanthropist Bill Gates, whose foundation pledged $1.6 billion.
Gavi also launched a new initiative to purchase potential COVID-19 vaccines, scale-up production and support delivery to developing nations, which raised $567 million in seed money.
"Together, we rise to fulfil the greatest shared endeavour of our lifetimes -- the triumph of humanity over disease," said British Prime Minister Boris Johnson, who hosted the summit.
"Today we make the choice to unite, to forge a path of global cooperation."
Scientists around the world are racing to develop and test a coronavirus vaccine and United Nations Secretary General Antonio Guterres said it must be available to everyone.
"A vaccine must be seen as a global public good -- a people's vaccine, which a growing number of world leaders are calling for," he said in a video message.
There needs to be "global solidarity to ensure that every person, everywhere, has access".
The pandemic has exposed new ruptures in international cooperation, notably with US President Donald Trump's decision to pull out of the World Health Organization (WHO).
But Gavi chief executive Seth Berkley insisted there must be a "global perspective".
"At the end of the day, if you have large outbreaks of COIVD anywhere in the world, it threatens the world," he said.