“…22 Regarding safety of the vaccine, multiple studies have shown that Zostavax® is well-tolerated and that side reactions are generally mild. 20,20,[23][24][25][26] However, as the mean follow-up time of the SPS was limited to 3.1 y, 20,21 the duration of the vaccine protection is still unknown. A short-term persistence substudy (STPS) of the SPS recently showed that vaccine efficacy persists for at least 7 y, but also Herpes zoster (HZ) is a common disease among elderly, which may develop into a severe pain syndrome labeled postherpetic neuralgia (PHN).…”