The vaccine was one of the H1N1 vaccines approved for use by the European Commission in September 2009, upon the recommendations of the European Medicines Agency (EMEA).[3] The vaccine is only approved for use when an H1N1 influenza pandemic has been officially declared by the World Health Organization (WHO) or European Union (EU).[3] The vaccine was initially developed as a pandemic mock-up vaccine using an H5N1 strain.[4]