U.S. Air Force Tech. Sgt. Lori McCarty, 60th Healthcare Operations Squadron allergy immunization technician, fills an injection needle with the COVID-19 vaccine Dec. 22, 2020, at Travis Air Force Base, California. David Grant U.S. Air Force Medical Center is the largest Air Force medical facility and provides care to more than 276,000 Department of Defense and Veteran Affairs eligible beneficiaries. Essential medical personnel from the 60th Medical Group were the first to receive the vaccine at Travis AFB. (U.S. Air Force photo by Senior Airman Cameron Otte)