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 and will comply with the requirements of the protocol
• Written informed consent obtained from the subject/subject's LAR(s) prior to performance 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 by one of the following three methods:
• Clinically diagnosed HZ:

OR Laboratory diagnosed HZ: OR

• HZ diagnosed by an adjudication committee: Female subjects of non-childbearing potential may be enrolled in the study.
• Non-childbearing potential is defined as current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy, bilateral salpingectomy or post-menopause.
• 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 pregnancy test on the day of vaccination, and
• has agreed to continue adequate contraception for 2 months after completion of the vaccination series.

Exclusion Criteria

• Subjects who at time of study entry or during the maximum period of anticipated study participation are/will become part of the population recommended to receive a zoster vaccine per existing local or national immunization practices will be excluded from study participation.
• Use of any investigational or non-registered product other than the study vaccine during the period starting 30 days before the first dose of study vaccine, or planned use during the study period.
• Any medical condition that in the judgment of the investigator would make intramuscular 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 or associated with neurologic disease caused by VZV infection.
• Use or anticipated use of immunosuppressants or immune-modifying drugs during the period starting six months prior to study start and during the whole study period. This includes chronic administration of corticosteroids, long-acting immune-modifying agents or immunosuppressive/cytotoxic therapy
• Administration or planned administration of a vaccine not foreseen by the study protocol within the period starting 30 days before the first dose of study vaccine and ending 30 days after the last dose of study vaccine. However, licensed pneumococcal vaccines and non-replicating vaccines may be administered up until 8 days prior to dose 1 and/or dose 2 and/or at least 14 days after any dose of study vaccine.
• 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 vaccine/product
• Previous vaccination against VZV or HZ.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination
• History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine.
• Acute disease and/or fever at the time of enrolment.
• Administration of immunoglobulins and/or any blood products during the period starting 3 months before the first dose of study vaccine or planned administration during the study period.
• Pregnant or lactating female.
• Female planning to become pregnant or planning to discontinue contraceptive precautions in the period up to 2 months after completion of the vaccination series.