Senior Airman Sheena Boyd, a nurse assigned to the 910th Medical Squadron, administers a flu shot to an airman assigned to the 910th Airlift Wing, here, Oct. 3, 2015. It is an annual requirement for Department of Defense military personnel to receive the flu shot to help ensure their medical readiness to deploy and carry out missions anywhere around the globe. (U.S. Air Force photo/Staff Sgt. Rachel Kocin)