On June 28, 2013, FDA approved GlaxoSmithKline Biologicals' ("GSK") Flulaval® Quadrivalent (Influenza Virus Vaccine) for the 2013-2014 flu season. Flulaval® Quadrivalent protects against two influenza-A virus strains and two influenza-B virus strains and is approved for ages 3 and older. This season is the first time that vaccines protecting against more than three influenza strains will be commercially available. The other quadrivalent vaccines that are currently available include: Astrazeneca/Medimmune's FluMist® Quadrivalent, GSK's Fluarix Quadrivalent, and Sanofi's Fluzone® Quadrivalent.
Seasonal flu is caused by either type-A influenza strains or type-B influenza strains. Each year, the World Health Organization recommends that vaccines address the two type-A strains that are most common in humans, and the type-B strain that is expected to be the most predominant in the upcoming flu season. Vaccines that protect against three influenza strains are referred to as trivalent vaccines. "Trivalent influenza vaccines have helped protect millions of people against flu, but in six of the last 11 flu seasons, the predominant circulating influenza B strain was not the strain that public health authorities selected," said Dr. Leonard Friedland, V.P. and Head, GSK North America Vaccines Clinical Development and Medical Affairs. Dr. Friedland also noted that, "Trivalent vaccines do reduce influenza risk even in years when a vaccine strain-mismatch occurs, though quadrivalent influenza vaccines are the important next step in broadening strain coverage." For the 2013-2014 flu season, the World Health Organization recommended protection against a second type-B influenza strain.
Three other quadrivalent vaccines have been approved by FDA for the 2013-14 flu season. Fluarix Quadrivalent is an intramuscular vaccine that requires 1-2 doses depending on a person's age and/or vaccination history. It is approved for ages 3 and older. FluMist® Quadrivalent is a live, attenuated vaccine that is administered via intra-nasal spray in 1-2 doses depending on a person's age and/or vaccination history. It is approved for ages between 2 and 49 years. Fluzone® Quadrivalent is an intramuscular vaccine that requires 1-2 doses depending on a person's age and/or vaccination history. It is approved for ages 6 months and older.
Flulaval®, Fluarix, and Fluzone® also have trivalent versions that are approved for the 2013-14 season, while FluMist® is available only in the quadrivalent form. There are three trivalent versions of the Fluzone® vaccine. Fluzone® is an intramuscular vaccine that requires 1-2 doses depending on a patient's age and/or vaccination history. It is approved for ages 6 months and older. Fluzone® Intradermal uses an ultra-thin needle, and is a single dose injected into the skin rather than into muscle. It is approved for people between ages 18 and 64 years. Fluzone® High-Dose is for patients 65 and older who are at an increased risk of contracting the flu.
The Centers for Disease Control and Prevention recommends that everyone 6 months of age and older get a flu vaccine, preferably by October. For the 2013-2014 season, close to 140 million vaccines are being produced.