The Gates Foundation said it will commit $1.6 billion over the next five years to Gavi, the Vaccine Alliance, after the U.S. announced it would no longer contribute to the global health partnership.

Gavi helps provide vaccines to some of the world’s poorest children. Since its launch in 2000, the alliance says it has supported the immunization of more than 1.1 billion children across 78 countries, helping prevent an estimated 19 million deaths.

"I don’t know of anything with a higher impact per dollar in terms of saving and improving lives," Gates said. "Gavi is one of the best investments I’ve ever made—and one of the best investments countries can make today in the world’s future."

RELATED STORY | 'More people are going to die': A former CDC official's warning as new vaccine advisory panel meets

The Gates Foundation is Gavi’s largest private donor, having contributed $7.7 billion over the past 25 years. Before the recent U.S. government funding cuts, the United States was Gavi’s second-largest government donor, behind the United Kingdom.

The new pledge from the Gates Foundation was announced at the Global Summit: Health and Prosperity through Immunisation in Brussels, where world leaders committed more than $9 billion toward Gavi’s $11.9 billion funding goal for its next five-year strategic period, known as Gavi 6.0.

Through Gavi 6.0, the alliance aims to immunize 500 million children, potentially averting up to 9 million deaths and protecting against outbreaks of diseases such as cholera, mpox and Ebola.