Study to Evaluate Immunogenicity and Safety of GSK Biologicals' Herpes Zoster Subunit (HZ/su) Vaccine at 9 and 10 Years After Vaccine Administration and Assessment of Re-vaccination With 2 Additional Doses at 10 Years After Initial Vaccination, in Healthy Subjects Aged 60 Years of Age(YOA) and Older

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, vaccination visits, availability for follow-up contacts). * Written informed consent obtained from the subject prior to performance of any study specific procedure. * Previous participation in study ZOSTER-003 (NCT00434577), in group 50 µg gE / AS01B, and who completed the vaccination course (2 doses of HZ/su) in study ZOSTER-003 (NCT00434577). * Subjects are expected to enter the study (or complete Visit 1) as of the time they turn 108 months after first vaccination of previous vaccination course with HZ/su and not later than 111 months. Exclusion Criteria: * Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine during the period starting 30 days before the first study visit (Day -29 to Day 0), or planned use during the study period. * 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 (\>14 consecutive days of prednisone at a dose…