A Long-term Follow-up Study (ZOE-LTFU) of Two Studies 110390 (ZOSTER-006) and 113077 (ZOSTER-022) to Assess the Efficacy, Safety, and Immunogenicity Persistence of GSK Biologicals' Herpes Zoster Subunit (HZ/su) Vaccine and Assessment of 1 or 2 Additional Doses in Two Subgroups of Older Adults

Inclusion Criteria

• Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the diary cards, return for follow-up visits, ability to have scheduled contacts to allow evaluation during the study). Or subjects with a caregiver who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the diary cards, availability for follow-up contacts).
• Written informed consent obtained from the subject prior to performance of any study specific procedure.
• Subject who participated in ZOSTER-006 or ZOSTER-022 studies and received at least one dose of HZ/su vaccine.

Additional inclusion criteria for the 1-Additional Dose Revaccination and Control groups, ONLY:

• Female subjects of non-childbearing potential may be enrolled in this study.
• Non-childbearing potential is defined as pre-menarche, current tubal ligation, hysterectomy, ovariectomy or post-menopause.
• Female subjects of childbearing potential may be enrolled in this 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 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 (pharmaceutical product or device) at the time of enrolment or planned use during the study period.
• Previous vaccination against Varicella Zoster Virus (VZV) or HZ and/or planned administration during the study of a VZV or HZ vaccine (including an investigational or non-registered vaccine other than the HZ/su vaccine administered in studies ZOSTER-006/022).
• Chronic administration (defined as ≥ 14 consecutive days in total) of immunosuppressants or other immune-modifying drugs during the period starting six months prior to Visit Month 0 of study ZOSTER-049 or expected administration at any time during the study period. For corticosteroids, this will mean prednisone ≥ 20 mg/day or equivalent. A prednisone dose of 14 consecutive days) of oral and/or parenteral antiviral agents that are active against VZV (acyclovir, valacyclovir, famciclovir, etc. ) and planned to be used during the study period for an indication other than to treat suspected or confirmed HZ or an HZ-related complication (topical use of these antiviral agents is allowed).
• Important underlying illness that in the opinion of the investigator would be expected to interfere significantly during the study.

Additional exclusion criteria for the 1-Additional Dose Revaccination and Control groups, only:

• Subjects who experienced an SAE from first vaccination in the previous ZOSTER-006/022 studies to enrolment in study ZOSTER-049 that was considered related to study vaccine by either the investigator or the sponsor.
• Subjects with a new onset of a pIMD or exacerbation of a pIMD from first vaccination in the previous ZOSTER-006/022 studies to enrolment in study ZOSTER-049.
• Use of any investigational or non-registered product (pharmaceutical product or device) within 30 days preceding the first dose of study vaccine or planned use during the study period.
• Administration or planned administration of any other immunizations within 30 days before the first study vaccination or scheduled within 30 days after study vaccination. However, licensed non-replicating vaccines (i.e., inactivated and subunit vaccines, including inactivated and subunit influenza vaccines for seasonal or pandemic flu, with or without adjuvant) may be administered up to 8 days prior to each dose and/or at least 14 days after any dose of study vaccine.
• 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 (such as material