The U.S. government has reached a deal with Pfizer to purchase 100 million more doses of the vaccine developed jointly with BioNTech.

A Pfizer-BioNTech COVID-19 vaccine shot is ready to be administered to Vice President Mike Pence at the Eisenhower Executive Office Building on the White House complex​, Washington, Friday, Dec. 18, 2020. (AP Photo/Andrew Harnik)