The United States Food and Drug Administration (FDA) has approved France-based Sanofi's Fluzone High-Dose Quadrivalent (Influenza Vaccine) intended for use in adults, aged 65 and over, it was reported yesterday.

The United States regulator approved the trivalent influenza vaccine in 2009, for the two influenza A strains and one influenza B strain.

The vaccine's quadrivalent formulation includes an additional influenza B strain. Following the approval of its supplemental biologics license application, the product can be used in the United States to protect older people from influenza disease caused by influenza A and B strains present in the vaccine. The product's approval was driven by the results of a phase three immunogenicity and safety study.