U.S. Air Force Lt. Col. Sandeep Gill, 489th Bomb Group flight surgeon, explains how the COVID-19 vaccine works to the first group of Reserve Citizen Airmen in the unit to take it, Feb. 7, 2021 at Dyess Air Force Base, Texas. Gill, who is an oncologist in his civilian career, endured multiple hardships after arriving in in the United States as a teenager. He developed a resiliency skillset to overcome adversity and reach his goal of serving in the military. (U.S. Air Force photo by Senior Master Sgt. Ted Daigle)