President Joe Biden is expected to announce a “historic” US donation of half a billion Covid-19 vaccine doses for 92 poorer countries today (Thursday), the White House has said.

According to AFP, the US is buying 500 million doses of the Pfizer-BioNTech vaccine, including 200 million set to be delivered around the world by the end of this year. The remainder will be sent out by June 2022, the White House said in a statement.

This “largest ever purchase and donation of vaccines by a single country” will “help supercharge the global fight against the pandemic,” the White House said.

Dismissing suggestions that the United States is in a so-called vaccine diplomacy contest with Russia and China, the White House described its initiatives as a return to multilateral action after the nationalist isolationism of Donald Trump's presidency.

The vaccines will be distributed through the international Covax program to “low and lower-middle income nations.”