Immunogenicity and Safety Study of GlaxoSmithKline (GSK) Biologicals' Herpes Zoster Subunit (HZ/su) Vaccine (GSK1437173A) in Adults ≥ 65 Years of Age With and Without Zostavax® Vaccination at Least 5 Years Earlier

The study will evaluate two parallel groups of 200 adults ≥ 65 YOA; one group (Prev-Zvax) with a previous Zostavax® vaccination at least 5 years earlier, versus the other group without a previous Zostavax® vaccination (No prev-Zvax). The goal of this study is to generate immunogenicity, safety and reactogenicity data for the respective vaccines.