Influenza vaccine. Pre-filled syringes containing the influenza (flu) vaccine Fluarix. The vaccine contains inactivated virions, or particles, of four strains of the flu virus. The strains are those thought most likely to cause outbreaks in 2004 and 2005, and are chosen by the World Health Organisation and the European Union. Vaccines provide protection against disease by priming the body's immune system, without causing infection. White blood cells are produced that can fight any future infection with the same or similar strains of flu virus. Due to the viruses ability to produce new strains, a new vaccine is needed each year. Fluarix is produced by GlaxoSmithKline.