82-year-old Brian Pinker receives the Oxford University/AstraZeneca COVID-19 vaccine from nurse Sam Foster at the Churchill Hospital in Oxford, England, Monday, Jan. 4, 2021. Pinker, a retired maintenance manager received the first injection of the new vaccine developed by between Oxford University and drug giant AstraZeneca. (Steve Parsons/Pool Photo via AP), APTOPIX

A resident of a nursing home gets an injection of the COVID-19 vaccine in Cologne, Germany, Sunday, Dec. 27, 2020. The first shipments of coronavirus vaccines developed by BioNTech and Pfizer have arrived across the European Union, authorities started to vaccinate the most vulnerable people in a coordinated effort on Sunday. (AP Photo/Martin Meissner), APTOPIX

Ninety-two year-old nursing home resident Gertrud Vogel gets an injection of the COVID-19 vaccine in Cologne, Germany, Sunday, Dec. 27, 2020. The first shipments of coronavirus vaccines developed by BioNTech and Pfizer have arrived across the European Union, and authorities started to vaccinate the most vulnerable people in a coordinated effort on Sunday. (AP Photo/Martin Meissner), APTOPIX

A resident of a nursing home reacts as she gets an injection of the COVID-19 vaccine in Cologne, Germany, Sunday, Dec. 27, 2020. The first shipments of coronavirus vaccines developed by BioNTech and Pfizer have arrived across the European Union, authorities started to vaccinate the most vulnerable people in a coordinated effort on Sunday. (AP Photo/Martin Meissner), APTOPIX

Efstathia Kambissiouli, left, a Greek nurse working in a state hospital intensive care, receives an injection with a dose of COVID-19 vaccine, in Athens, Sunday, Dec. 27, 2020. Kambissiouli was the first person to be vaccinated against coronavirus in Greece, followed a few minutes later by Michalis Giovanidis, a nursing home resident. (AP Photo/Yorgos Karahalis, Pool)

Efstathia Kambissiouli, left, a Greek nurse working in a state hospital intensive care unit, receives an injection with a dose of COVID-19 vaccine, in Athens, Sunday, Dec. 27, 2020. Kambissiouli was the first person to be vaccinated against coronavirus in Greece, followed a few minutes later by Michalis Giovanidis, a nursing home resident. AP Photo/Yorgos Karahalis, Pool)

Mississippi Air Guard Tech. Sgt. Exstrella Smith withdraws a dose of the Moderna COVID-19 vaccine for injection into the arm of a Mississippi Air or Army National Guard service member who serves as a first responder, Wednesday, Dec. 23, 2020, in Flowood, Miss. One hundred doses of the vaccine were administered to both Mississippi Air and Army National Guard service members who currently assist with the administering of the COVID-19 test at Mississippi Department of Health drive through community testing sites across the state. (AP Photo/Rogelio V. Solis)

Dr. Lisa Jackson, a senior investigator at the Kaiser Permanente Washington Health Research Institute, poses for a photo, Sunday, March 15, 2020, in Seattle. Jackson is leading the first-stage safety study clinical trial of a potential vaccine for COVID-19, the disease caused by the new coronavirus, which was given to the first volunteer in the study by injection, Monday, March 16 in Seattle. (AP Photo/Ted S. Warren)

Dr. Lisa Jackson, a senior investigator at the Kaiser Permanente Washington Health Research Institute, works in her office with an image of COVID-19 taped to her door, Sunday, March 15, 2020, in Seattle. Jackson is leading the first-stage safety study clinical trial of a potential vaccine for COVID-19, the disease caused by the new coronavirus, which was given to the first volunteer in the study by injection, Monday, March 16. (AP Photo/Ted S. Warren)