The FDA has approved a quadrivalent influenza vaccine for use in adults and children aged 6 months and older during the 2013-2014 season.

Fluzone Quadrivalent (Sanofi Pasteur) will be the only influenza vaccine that protects children younger than 2 years against four strains of influenza, the manufacturer announced in a press release.

Previously, the FDA approved FluMist Quadrivalent (Medimmune) for children aged 2 years and older, and Fluarix Quadrivalent (GlaxoSmithKline) for those aged 3 years and older. All three quadrivalent vaccines will include two strains of the influenza A and two strains of the influenza B subtypes.

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Last year, an FDA advisory panel recommended switching from the traditional trivalent influenza vaccine formulation — which included two influenza A strains and one influenza B strain — to a quadrivalent formulation due to difficulty predicting the dominant circulating influenza B strain in a given season.

In six of the past 12 influenza seasons, the dominating circulating influenza B strain was different from the strain selected for inclusion in the trivalent vaccine, the manufacturer said in a press release. In years when the dominant influenza B strain was correctly predicted, another B strain also caused a substantial number of illnesses.

“In recent years, up to 44 percent of influenza-associated deaths in children and adolescents 18 years of age and younger were due to influenza B,” the manufacturer said. “Protection against the type B flu strain may be an especially important factor that healthcare providers consider when immunizing children since influenza B causes a substantial number of illnesses, hospitalizations and deaths in the pediatric population.”

Fluzone Quadrivalent will be available as prefilled syringes and single-dose vials for intramuscular administration.