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…