Herpes zoster is caused by the reactivation of latent varicella-zoster virus (VZV) which stays in latency after its primary infection. Immunosenescence contributes significantly to elevating morbidity associated with aging. Vaccination plays a key role in reducing the disease burden of zoster and the associated complications. We are conducting a study entitled "A Randomized, Blinded, Placebo- and Active-Controlled, Adaptive Phase 2 Clinical Trial to Evaluate the Immunogenicity and Safety of SYS6017 (a Herpes Zoster mRNA Vaccine) in Healthy Participants Aged 40 Years and Above".