Study to Evaluate Efficacy, Safety and Immunogenicity of GSK Biologicals' Herpes Zoster (HZ) Vaccine GSK1437173A in Adults Aged 50 Years and Older

The purpose of this observer-blind study is to evaluate the efficacy, safety and immunogenicity of GSK Biologicals' candidate Herpes Zoster (HZ) vaccine in adults aged ≥ 50 years.

Two studies \[ZOSTER-006 (NCT01165177) and ZOSTER-022 (NCT01165229)\] are being conducted concurrently to evaluate efficacy of GSK1437173A vaccine. A pooled analysis of data from both studies combined will be conducted contingent on each study achieving its objectives. The protocol posting of study ZOSTER-022 also deals with the outcome measures related to the pooled analysis.

This protocol summary has been updated following Protocol Amendment 4 changes to study objectives and endpoints and the analyses of the objectives in 2 steps.

Step 1 will include analyses of the following objectives of ZOSTER-006 (NCT01165177): all HZ VE objectives and all reactogenicity/safety and immunogenicity objectives. At step 2, all objectives of study ZOSTER-006 (NCT01165177) will be analyzed. Objectives already analyzed at step 1 will be re-analyzed (confirmatory descriptive in case of inferential analysis at step 1 or descriptive analysis otherwise). At step 2, pooled analyses of studies ZOSTER-006 (NCT01165177) and ZOSTER-022 (NCT01165229) are planned; overall PHN VE in subjects ≥ 70 YOA, and other pre-specified endpoints will be analyzed.

Eligibility Criteria:
Inclusion Criteria:

* Subjects who the investigator believes will comply with the requirements of the protocol;
* Written informed consent obtained from the subject;
* A male or female aged 50 years or older at the time of the first vaccination;
* Female subjects of non-childbearing potential may be enrolled in the study;

For this study population, non-childbearing potential is defined as current tubal ligation, hysterectomy, ovariectomy or post-menopause.

OR Female subjects of childbearing potential may be enrolled in the study, if the subject has practiced adequate contraception for 30 days prior to vaccination, and has a negative urine pregnancy test on the day of vaccination, and has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series;

Exclusion Criteria:

* Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the first dose of study vaccine, or planned use during the study period;
* Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product;
* Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease or immunosuppressive/cytotoxic therapy;
* History of HZ;
* Previous vaccination against varicella or HZ;
* History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. Additionally, consider allergic reactions to other material or equipment related to study participation;
* Significant underlying illness that in the opinion of the investigator would be expected to prevent completion of the study;
* Receipt of immunoglobulins and/or any blood products within the 90 days preceding the first dose of study vaccine or planned administration during the study period;
* Administration or planned administration of any other immunizations within 30 days before the first or second study vaccination or scheduled within 30 days after study vaccination. However, licensed non-replicating vaccines may be administered up to 8 days prior to each dose and/or at least 14 days after any dose of study vaccine;
* Any other condition that, in the opinion of the investigator, might interfere with the evaluations required by the study;
* Acute disease and/or fever at the time of enrollment;
* Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose.
* Pregnant or lactating female;
* Female planning to become pregnant or planning to discontinue contraceptive precautions.