Immunogenicity and Safety of an Adjuvanted Herpes Zoster Subunit Vaccine in Older Adults Previously Vaccinated with a Live-Attenuated Herpes Zoster Vaccine: A Phase III, Group-Matched, Clinical Trial

Background Herpes zoster (HZ), caused by reactivation of varicella-zoster virus (VZV), typically manifests as a dermatomal rash and can lead to postherpetic neuralgia (PHN). HZ and PHN risk increase with age. Efficacy against HZ induced by a live-attenuated zoster vaccine (ZVL; Merck) declines following vaccination (21% in years 5–12 post-vaccination). To ensure protection, revaccination can be considered. Therefore, we assessed immunogenicity and safety of HZ/su, a non-live candidate vaccine containing VZV glycoprotein E (gE) subunit and AS01B adjuvant system (GSK), in adults previously vaccinated with ZVL ≥5 years before, (HZ-PreVac) compared with adults not vaccinated with ZVL (HZ-NonVac).