Immunogenicity and Safety Study of GSK Biologicals' Herpes Zoster Vaccine With Various Formulations in Adults >= 50 Years

Inclusion Criteria:

• A male or female 50 years of age or above at the time of the first vaccination;
• Written informed consent obtained from the subject;
• Subjects who the investigator believes that they can and will comply with the requirements of the protocol should be enrolled in the study;
• If the subject is female, she must be of non-childbearing potential, or if she is of childbearing potential, she must practice adequate contraception for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for 2 months after completion of the vaccination series.

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;
• Chronic administration (defined as more than 14 consecutive days) of immunosuppressants or other immune-modifying drugs within three months prior to the first vaccine dose.
• Planned administration/ administration of a vaccine not foreseen by the study protocol within one month before the first study vaccination or scheduled within 30 days after study vaccination;
• Previous vaccination against HZ;
• Previous vaccination against varicella;
• History of HZ;
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine;
• Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease or immunosuppressive/cytotoxic therapy;
• Administration of immunoglobulins and/or any blood products within the 3 months preceding the first injection of study vaccine or planned administration during the study period;
• Acute disease at the time of enrolment.
• Any other condition that, in the opinion of the investigator, might interfere with the evaluations required by the study;
• History of or current drug and/or alcohol abuse;
• Pregnant or lactating female;
• Female planning to become pregnant or planning to discontinue contraceptive precautions if of childbearing potential.