U.S. Air Force Staff Sgt. Sarah Ellis, 52nd Medical Operations Squadron noncommissioned officer in charge of allergy and immunizations from Mount Hood, Ore., April 2, 2013. Ellis fills a syringe with a vaccine to administer to a patient. Vaccines provide our airmen with the ability to fight off infectious diseases. (U.S. Air Force photo by Airman 1st Class Kyle Gese/Released)