Mission essential – Allison Bir, immunizations technician Published March 19, 2013 VANCE AIR FORCE BASE, Okla. -- Tech. Sgt. Allison Bir is the NCO in charge of the Immunizations Clinic with the 71st Medical Operations Squadron at Vance Air Force Base. Immunizations technicians like Bir are essential to the mission here. They ensure the men and women of Team Vance are protected against diseases wherever they may be deployed. Combat ready warriors are just one part of the mission at the 71st Flying Training Wing.