FluMist Quadrivalent, a vaccine
to prevent seasonal influenza
in people ages 2 years through 49 years, has been approved today by the U.S. Food and Drug Administration. FluMist Quadrivalent is the first influenza vaccine to contain four strains of the influenza virus
, two influenza A strains and two influenza B strains.
Like the already approved FluMist (trivalent), the quadrivalent vaccine contains weakened forms of the virus strains and is administered as a spray into the nose.
There are two types of influenza viruses that cause illness and death in people: influenza A and B. Each year, the FDA-approved seasonal influenza vaccine includes three strains of influenza virus, two strains of influenza A and one of influenza B. During a typical influenza season, there may be two different influenza B strains circulating, or the B strain selected for inclusion in the trivalent influenza vaccine may not be the influenza B strain that eventually circulates causing illness. The inclusion of a second B strain in FluMist Quadrivalent increases the likelihood of adequate protection against circulating influenza B strains.
"Illness caused by Influenza B virus affects children, particularly young and school-aged, more than any other population," said Karen Midthun, M.D., director of the FDA's Center for Biologics Evaluation and Research. "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."