Master Sgt. Steven Burns, 28th Medical Operations Squadron NCO in charge of immunizations, prepares an influenza vaccine for an Airman at Ellsworth Air Force Base, S.D., March 13, 2012. The vaccination is mandatory for all military members and can be received at the 28th MDOS immunizations clinic Monday through Friday, from 7:30 a.m. to 4 p.m. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)