Safety and Immunogenicity Study of GlaxoSmithKline's Herpes Zoster Subunit Vaccine (HZ/su) When Given on a Two-dose Schedule to Adults at Least 50 Years of Age (YOA) With a Prior Episode of Herpes Zoster

Inclusion Criteria:

• Subjects and/or subject's LAR(s) who, in the opinion of the investigator, can andwill comply with the requirements of the protocol

• Written informed consent obtained from the subject/subject's LAR(s) prior toperformance of any study specific procedure.

• A male or female ≥ 50 YOA at the time of the first vaccination.

• Subjects with a history of HZ. Confirmation of the prior HZ diagnosis can be done byone of the following three methods:

• Clinically diagnosed HZ:

OR Laboratory diagnosed HZ: OR

• HZ diagnosed by an adjudication committee: Female subjects of non-childbearingpotential may be enrolled in the study.

• Non-childbearing potential is defined as current bilateral tubal ligation orocclusion, hysterectomy, bilateral ovariectomy, bilateral salpingectomy orpost-menopause.

• Female subjects of childbearing potential may be enrolled in the study if thesubject:

• has practiced adequate contraception for 30 days prior to vaccination, and

• has a negative pregnancy test on the day of vaccination, and

• has agreed to continue adequate contraception for 2 months after completion of thevaccination series.

Exclusion Criteria:

• Subjects who at time of study entry or during the maximum period of anticipatedstudy participation are/will become part of the population recommended to receive azoster vaccine per existing local or national immunization practices will beexcluded from study participation.

• Use of any investigational or non-registered product other than the study vaccineduring the period starting 30 days before the first dose of study vaccine, orplanned use during the study period.

• Any medical condition that in the judgment of the investigator would makeintramuscular injection unsafe.

• Onset of HZ in the past 6 months or any ongoing symptoms from a prior HZ episode.

• Chronic antiviral use for HZ prophylaxis.

• History of >1 prior episode of HZ.

• A history of disseminated HZ, cutaneous or associated with visceral disease orassociated with neurologic disease caused by VZV infection.

• Use or anticipated use of immunosuppressants or immune-modifying drugs during theperiod starting six months prior to study start and during the whole study period.This includes chronic administration of corticosteroids, long-actingimmune-modifying agents or immunosuppressive/cytotoxic therapy

• Administration or planned administration of a vaccine not foreseen by the studyprotocol within the period starting 30 days before the first dose of study vaccineand ending 30 days after the last dose of study vaccine. However, licensedpneumococcal vaccines and non-replicating vaccines may be administered up until 8days prior to dose 1 and/or dose 2 and/or at least 14 days after any dose of studyvaccine.

• Concurrently participating in another clinical study, at any time during the studyperiod, in which the subject has been or will be exposed to an investigational or anon-investigational vaccine/product

• Previous vaccination against VZV or HZ.

• Any confirmed or suspected immunosuppressive or immunodeficient condition, based onmedical history and physical examination

• History of any reaction or hypersensitivity likely to be exacerbated by anycomponent of the vaccine.

• Acute disease and/or fever at the time of enrolment.

• Administration of immunoglobulins and/or any blood products during the periodstarting 3 months before the first dose of study vaccine or planned administrationduring the study period.

• Pregnant or lactating female.

• Female planning to become pregnant or planning to discontinue contraceptiveprecautions in the period up to 2 months after completion of the vaccination series.