This phase II, open label, is designed as a seasonal study to support annual strain update evaluating the safety, clinical tolerability and immunogenicity of the 2007-2008 formulation of Novartis Vaccines' adjuvanted, subunit influenza vaccine in adults with underlying chronic diseases

Inclusion Criteria:

• 18 to 64 years of age adult volunteers, mentally competent, willing and able to give written informed consent prior to study entry, suffering from at least one of these chronic diseases: hypertension, heart disease, chronic obstructive pulmonary disease (COPD) or asthma, hepatic or renal insufficiency, arteriosclerotic disease or insulin dependent diabetes mellitus

Exclusion Criteria:

• Hypersensitivity to ovalbumin, chicken protein, chicken feathers, influenza viral protein, kanamycin and neomycin sulphate or any other component of the vaccine;
• History of neurological symptoms or signs, or anaphylactic shock following administration of any vaccine;
• Known or suspected impairment/ alteration of immune function;
• Having received within the past 12 months more than one injection of influenza vaccine
• Any condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives