The United States will purchase and donate half a billion doses of Pfizer’s COVID-19 vaccine to 92 low- and lower middle-income countries and the African Union through the end of 2021 and into the beginning of 2022, the Biden administration announced Thursday (June 10). The White House described the announcement as a historic action that will “help supercharge the global fight” against the pandemic. The 500 million doses add to the 80 million COVID-19 vaccine doses the United States has...