The US Food and Drug Association has approved Sanofi's supplemental biologics license application for Fluzone Quadrivalent, which the company says is the first-and-only four-strain influenza vaccine for patients as young as six months of age.

The French drugmaker's Sanofi Pasteur unit notes that like its existing Fluzone vaccine, which is administered to more than 50 million people in the USA each year, the new jab is licensed for use in adults and adolescents, as well as children. The firm noted that the 2013 season will be the first in which quadrivalent influenza vaccines will be available in the USA; until this year, they included only one B strain but Fluzone Quadrivalent includes two A strains and two B strains.

Sanofi Pasteur says that epidemics of influenza B occur every two to four years in all age groups and in recent years, up to 44% of flu-associated deaths in children and adolescents 18 years of age and younger were due to influenza B. David Greenberg, vice president of scientific and medical affairs at Sanofi Pasteur, said that "protection against the type B flu strain may be an especially important factor that healthcare providers consider when immunising children since influenza B causes a substantial number of illnesses, hospitalisations and deaths in the paediatric population".

Sanofi's vaccine will compete with GlaxoSmithKline's Fluarix Quadrivalent and FluMist Quadrivalent from AstraZeneca's MedImmune unit, both of which have already been approved by the FDA. However, FluZone Quadrivalent may have an advantage as the other two can only be given to children aged two and upwards.