FILE - In this Saturday Jan. 2, 2021 file photo, doses of the COVID-19 vaccine developed by Oxford University and U.K.-based drugmaker AstraZe…

FILE - In this Saturday Jan. 2, 2021 file photo, doses of the COVID-19 vaccine developed by Oxford University and U.K.-based drugmaker AstraZe…

FILE - This Monday, Dec. 14, 2020 file photo, shows a vial of the Pfizer-BioNTech vaccine for COVID-19 at Hartford Hospital in Hartford, Conn.…

FILE - In this Tuesday, Dec. 8, 2020 file photo, British Prime Minister Boris Johnson watches as nurse Rebecca Cathersides administers the Pfi…

FILE - In this Friday Jan. 8, 2021 file photo, a member of staff prepares to administer the Pfizer-BioNtech COVID-19 vaccine to a member of th…

FILE - In this Tuesday, Dec. 8, 2020 file photo, a man enters the Royal Victoria Hospital, one of several hospitals around Britain that are ha…

FILE - In this Monday, Jan. 4, 2021 file photo, 82-year-old Brian Pinker receives the Oxford University/AstraZeneca COVID-19 vaccine from nurs…

FILE - In this Tuesday Dec. 8, 2020 file photo, 90 year old Margaret Keenan, the first patient in the UK to receive the Pfizer-BioNTech COVID-…

FILE - In this Saturday Jan. 2, 2021 file photo, Assistant Technical Officer Lukasz Najdrowski unpacks doses of the COVID-19 vaccine developed…

FILE - This Tuesday Dec. 8, 2020 file photo shows Pfizer-BioNTech COVID-19 vaccine bottles at Southmead Hospital in Bristol, England, as the m…