▶ Watch Video: CBSN Washington — President Biden on Thursday will deliver remarks on the COVID-19 vaccination program as his administration prepares to buy 500 million doses of Pfizer’s coronavirus vaccine for the global supply. Mr. Biden’s speech will cap the end of his first full day in the United Kingdom, where he touched down Wednesday for the Group of 7 summit. The trip is his first outside the United States since assuming office in January. How to watch President Biden’s remarks What: President Biden delivers remarks on the COVID-19 vaccination program and the effort to defeat COVID-19 around the world When: Thursday, June 10 Time: 1:15 p.m. ET Location: St. Ives, Cornwall, United Kingdom Online stream: Live on CBSN in the player above or on your mobile or streaming device The White House announced Thursday that it would be purchasing 500 million doses of the two-shot vaccine from Pfizer and German partner BioNTech to donate to the world’s supply, which is enough to fully inoculate 250 million people against COVID-19. The U.S. will deliver 200 million doses by the end of the year and the remaining 300 million doses in the first half of 2022, according to the White House. Vaccines will begin shipping in August. The doses will be distributed through COVAX, the global initiative that aims to ensure equitable access to coronavirus testing and vaccines, and given to 92 low- and middle-income countries and the African Union. Senior administration officials told reporters the Biden administration will use $2 billion already pledged to COVAX to pay for Pfizer’s shots, while the remaining $1.5 billion will come from money already available in the American Rescue Plan, the $1.9 trillion coronavirus relief package enacted in March. Mr. Biden has already pledged to donate at least 80 million vaccine doses from the U.S. supply by the end of June.