The US is to distribute half a billion shots of the Pfizer vaccine to nearly 100 poorer countries.
Some 200 million doses will be given out this year and 300 million in 2022.
It comes as US President Joe Biden said before leaving for the G7 summit in Cornwall that he would be announcing a vaccine strategy for the world.
The US would pay for the doses at a “not-for-profit” price, according to the New York Times, which said the plan could be officially announced on Thursday.
The shots will go to 92 lower-income countries and the African Union, sources told the Reuters news agency.
America is well advanced in its vaccine rollout but campaigners have called for richer countries to do more to help protect developing nations.
It’s understood that the half a billion jabs will be distributed via the World Health Organization’s Covax scheme, which is trying to remedy so-called “vaccine apartheid” by working with governments and manufacturers to ensure an equitable distribution of jabs.
It aims to deliver two billion doses in 2021, and 1.8 billion doses to 92 lower income economies by early 2022.