The present invention relates to monovalent influenza vaccine formulations and vaccination regimes for immunising against influenza disease, their use in medicine, in particular their use in augmenting immune responses to various antigens, and to methods of preparation. In particular, the invention relates to monovalent influenza immunogenic compositions comprising an influenza antigen or antigenic preparation thereof from an influenza virus strain being associated with a pandemic outbreak or having the potential to be associated with a pandemic outbreak, in combination with an oil-in-water emulsion adjuvant comprising a metabolisable oil, a sterol and/or a tocopherol such as alpha tocopherol, and an emulsifying agent.