CSP#403C, the Long-Term Persistence Substudy, was initiated in March 2006 and enrolled 6867 vaccine recipients from the main efficacy study. Enrollment was restricted to vaccine recipients from the main efficacy study with no history of herpes zoster. This study was initiated to complete an additional five-years of follow-up post-vaccination. The objective of this study was to estimate the longer-term durability of zoster vaccine efficacy by following a cohort of vaccine recipients from the primary efficacy study for three study outcomes: 1) the incidence of herpes zoster, 2) the incidence of postherpetic neuralgia (PHN), and 3) the burden of illness (BOI) due to herpes zoster. The study completed surveillance for new cases of herpes zoster as of December 2010 and completed the follow-up of the last case of herpes zoster in February 2011. All study sites have been closed out. This substudy has been completed and is in the final analysis phase.