FDA approved MedImmune’s FluMist® Quadrivalent (influenza Vaccine Live, Intranasal) flu vaccine. The vaccine is the first quadrivalent flu vaccine to achieve FDA approval, the firm states. Currently licensed trivalent vaccines protect against two type A strains and one type B strain. In contrast, the quadrivalent vaccine protects against influenza B strains from both the Yamagata and Victoria lineages that have been circulating in the U.S. since the early 2000’s, as well as the two strains of type A influenza (A/H1N1 and A/H3N2).
Clearance was based on data from pivotal trials in children and adults aged 2–49 years, in which FluMist quadrivalent was compared with two trivalent formulations of MedImmune’s already licensed FluMist seasonal influenza vaccine.
According to CDC estimates, about 2.7 million fewer people in the U.S. would have contracted flu between 2001 and 2009, if all influenza vaccines had been quadrivalent, states professor Stan Block, M.D., professor of clinical pediatrics at the University of Kentucky Colelge of Medicine and the University of Louisville School of Medicine. “In the U.S., in 5 of the 10 influenza seasons between 2001 and 2011, the predominant circulating influenza B lineage was different from the one selected for inclusion in the trivalent vaccines,” he states.