FDA approves GSK's quadrivalent flu vaccine

The FDA approved GSK's four-strain seasonal flu vaccine.

The FDA gave the OK to GlaxoSmithKline's ($GSK) new four-strain seasonal flu vaccine, which the company said will become available for the 2013-2014 flu season.

Fluarix Quadrivalent is approved for use in children age 3 and older and in adults, and protects against disease caused by seasonal flu virus subtypes A and B. The typical flu vaccine on the market now protects against three strains: Two A virus strains and one B strain. GSK's product adds protection against a second B strain.

Each year, the viruses included in the vaccine change based on international surveillance and scientists' estimations as to which types and strains of the flu will circulate. If the strains making the rounds don't match up with the strains found in the trivalent, or three-strain, vaccine, the incident of illness can increase across all age groups. Fluarix Quadrivalent tacks on that second B strain, providing an extra opportunity to match the circulating strain with the antidote.    

"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," Dr. Leonard Friedland, vice president and head of GSK North America Vaccines Clinical Development and Medical Affairs, said in a statement. "Fluarix Quadrivalent will help protect individuals against both B strains and from a public-health standpoint, can help decrease the burden of disease."

And that burden can sometimes be heavy. The 2011-2012 flu season set a record for the lowest and shortest peak of influenza-like illness, compared with other seasons, according to the Centers for Disease Control and Prevention. As of Sept. 21, only 34 pediatric deaths occurred. But during the 2009-2010 flu season, 282 pediatric deaths occurred. This number includes the 2009 H1N1 pandemic.

"So far this year, the CDC estimates that about one-third of B-strain flu cases have been caused by the B strain not included in this year's flu vaccine," Robert Perry, a GSK spokesman, told FierceVaccines. "Interestingly, this also means the strain protection choices made by the CDC for this year's flu vaccines were spot on; there's just an inherent limitation when you can only incorporate three-strain protection into a vaccine while there are four strains that cause illness that are ciruclating."

GSK, which already sells the FluLaval/Fluviral vaccine, will again jump into a market ripe with possibility. Only about 42% of people receive their flu shots--far below the CDC's target rate of 80%--meaning a large population remains untapped.

In November, the FDA approved Novartis' ($NVS) rapid-production flu vaccine Flucelvax, which is grown in mammal cells rather than in eggs.

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