Influenza vaccination. Syringe being used to inject an influenza (flu) vaccine into the upper arm of an elderly patient. An influenza vaccine contains dead influenza viruses. When injected, the vaccine stimulates the body's immune system to produce antibodies that protect against future infection by live influenza viruses. Vaccinations against influenza are usually short-lived because the virus mutates into new forms. Vaccination is mostly recommended for the elderly and the young, or anyone with respiratory or circulatory disease. This is an Influvac vaccine dated 2004/2005. Influvac is a sub-unit vaccine manufactured by Solvay Pharmaceuticals.