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

Immunogenicity and Safety Study of Different Formulations of GSK Biologicals' Herpes Zoster Vaccine 1437173A When Administered Twice in Adults Aged 50 Years and Older

The goal of this randomized observer-blind trial is to further refine the formulation of vaccines containing GSK1437173A in older adults by comparing the cellular and humoral immune responses and the safety profiles of the different formulations.

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.