U.S. Air Force Major Gwendolyn Walker, 48th Medical Operations Squadron flight commander, administers the 10,000th COVID-19 vaccine to Tech. Sgt. Christopher Rex, 48th Contracting Squadron contract specialist, at Royal Air Force Lakenheath, England, April 16, 2021. Personnel were prioritized to receive the vaccine based on the guidance from the Centers for Disease Control and Prevention and on the DoD COVID Task Force’s assessment of unique DoD mission requirements. (U.S. Air Force photo by Airman 1st Class Jessi Monte)