WASHINGTON — President Biden promised on Wednesday that his administration would buy 500 million doses of the Pfizer coronavirus vaccine, which it would then donate for distribution across the world. The new donation will mean that by 2022, the United States will have donated 1.1 billion doses of vaccine — far more than any other nation, but not nearly enough to account for the roughly 4 billion unvaccinated people around the world.

“America will become the arsenal of vaccines, as we were the arsenal for democracy during World War II,” President Biden said at a virtual summit with world leaders, where he made the announcement. 

Biden also reminded those leaders that