The FDA said it approved first quadrivalent vaccine to prevent seasonal influenza – FluMist Quadrivalent – a vaccine to prevent seasonal influenza in people ages 2 years through 49 years, and the first influenza vaccine to contain four strains of the influenza virus, two influenza A strains and two influenza B strains. Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research, said, “Illness caused by Influenza B virus affects children, particularly young and school-aged, more than any other population. A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts.”

http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm294057.htm