Senior Airman Caleb McCain, 507th Medical Squadron medical technician, withdraws a dose of the Moderna COVID-19 vaccine into a syringe Feb. 7, 2021, at Tinker Air Force Base, Oklahoma. More than 250 Reservists voluntarily received the first dose of the two-part Moderna COVID-19 vaccine series during the February unit training assembly. (U.S. Air Force photo by Tech. Sgt. Lauren Kelly)