Study to Evaluate the Response Rate to the Licensed Pneumovax 23™ in Elderly Population.

Inclusion criteria * Subjects who the investigator believes will comply with the requirements of the protocol. * A male or female \>= 65 years at the time of the first vaccination. * Written informed consent obtained from the subject. Exclusion criteria * Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the first dose of study vaccine, or planned use during the study period or participation to another pharmaceutical/vaccine study. * Previous vaccination against Streptococcus pneumoniae. * History of administration of an experimental vaccine containing MPL or QS21. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Planned administration of a vaccine not foreseen by the study protocol within 2 weeks before and after first dose of vaccines, excluding influenza vaccine which can be administered at any time, including co-administration with Pneumovax23™. * Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose. * Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection. * Current serious neurologic or mental disorders. * Inflammatory processes such as known chronic active infections (e.g.Hep B, C). * All malignancies (excluding non-melanic skin cancer) and lymphoproliferative disorders diagnosed or treated actively during the past 5 years. * Acute disease at the time of enrolment. * Chronic disease that might preclude participation to the whole study.