The FDA has approved the first influenza vaccine intended to protect against four strains of the virus, drug maker GlaxoSmithKline announced in a press release.

Fluarix Quadrivalent is indicated for children aged 3 years and older and adults, and will be available in time for the 2013-2014 flu season. The new quadrivalent influenza vaccine will contain two influenza B strains instead of one, in addition to the two influenza A strains currently used in trivalent influenza vaccines.

Since 2000, two influenza B virus strains — Victoria and Yamagata — have co-circulated to varying degrees each season. Because of the time involved in manufacturing influenza vaccine, a panel of experts chooses which strains to include in the vaccine months in advance. This process sometimes results in a mismatch between the influenza strains chosen for the vaccine and the circulating virus, increasing the risk for influenza-related morbidity across all age groups.

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In six of the last 11 influenza seasons, including last year’s vaccine, public health authorities failed to select the predominant circulating influenza B strain to include in the vaccine, GlaxoSmithKline noted.

Fluarix Quadrivalent is one of two influenza vaccines in development to include four strains of the virus. The other is being produced by Sanofi Pasteur, but has not yet received approval.

The most common adverse reactions in adults in clinical trials were pain at the injection site, muscle aches, headaches and fatigue. Among children aged 3 to 18 years, the most common adverse reactions were pain at the injection site, redness and swelling, whereas children 3 to 6 years commonly experienced drowsiness, irritability and loss of appetite.