The purpose of the current ZOSTER-101 long-term follow-up (LTFU) study of ZOSTER-049 (NCT02723773) study, an extension of ZOSTER-006 (NCT01165177) and ZOSTER-022 (NCT01165229) primary studies, is to assess the long-term vaccine efficacy (VE) against Herpes Zoster (HZ) (approximately 11-15 years post primary vaccination in ZOSTER-006/022 studies), persistence of immunogenicity and safety of GSK's Herpes Zoster subunit (HZ/su) vaccine in older adults. The persistence of immunogenicity and safety of 1 or 2 additional doses (0, 2-month schedule) of HZ/su vaccine administered to a small group of participants in ZOSTER-049 study (approximately 5 years after the initial vaccination in ZOSTER-006/022 studies) will also be assessed.

Inclusion Criteria:

• Participants and participant's caregiver, who, in the opinion of the investigator, can and are willing to comply with the requirements of the protocol.
• Written or witnessed/thumb printed informed consent obtained from the participant prior to performance of any study-specific procedure.
• Medically stable participants as established by medical history and clinical examination before entering into the study.
• Participants who completed ZOSTER-049 study (following at least 1 dose of HZ/su in ZOSTER-006/022 studies).

Exclusion Criteria:

Medical conditions

• Any clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.

Prior/Concomitant therapy

• Use of any investigational or non-registered product (drug, vaccine or medical device) for the treatment of HZ or Varicella Zoster Virus (VZV) infection at the time of enrolment or their planned use during the study period.
• Previous vaccination against 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 HZ/su administered in studies ZOSTER-006/022 or ZOSTER-049).

Prior/Concurrent clinical study experience

• Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention (drug/invasive medical device) for the prevention and/or treatment of HZ or VZV and which may have a possible activity against VZV.

IPD for this study will be made available via the Clinical Study Data Request site.

IPD will be made available within 6 months of publishing the results of the primary endpoints, a key secondary endpoints and safety data of the study.

Access is provided after a research proposal is submitted and has received approval from the Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension can be granted, when justified, for up to another 12 months.