PARIS - French healthcare group Sanofi and U.S. partner Translate Bio have started a Phase I clinical trial evaluating an mRNA-based investigational vaccine against seasonal influenza, the companies said on Tuesday.

The trial will evaluate the safety and immunogenicity of a monovalent flu vaccine candidate coding for the hemagglutinin protein of the A/H3N2 strain of the influenza virus.

Flu seasons dominated by A/H3N2 strain circulation activity tend to be more severe, especially among those considered at risk, such as older adults and younger children, the companies added.

(Reporting by Sudip Kar-Gupta; Editing by Clarence Fernandez) ((sudip.kargupta@thomsonreuters.com; +33 1 49 49 53 84;))