Support Annual Strain Update, Safety and Immunogenicity of an Inactivated, Adjuvanted Influenza Vaccine, Formulation 2007-2008, When Administered to Subjects 18-64 Years Affected by 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