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. This randomized, observer-blind, placebo-controlled, adaptive phase 1 trial aims to evaluate the safety and immunogenicity of an investigational zoster mRNA vaccine in healthy participants aged 40 years or more.
1. Healthy participants aged 40 years or more;
2. Be able to understand the study procedures and comply with the requirements of the protocol for the scheduled visits, voluntarily consent to participate in the study and sign the informed consent form (ICF);
3. Being in good health at the discretion of investigators based on medical history inquiry, physical examination, laboratory test and electrocardiograph examination;
4. For female participants of childbearing potential: no sexual activity or used effective contraceptive methods within one menstrual cycle before enrollment; no pregnancy plans and agree to used effective contraceptive methods with 8 months after enrollment.
1. History of zoster;
2. History of vaccination with varicella vaccine or zoster vaccine (including investigational vaccine);
3. Axillary temperature ≥ 37.1℃ on the day of enrollment or within 24 h before enrollment;
4. Have abnormal test or examination result that is of Grade 1 (inclusive) or more in accordance with the Guidelines for Adverse Event Grading Standards for Clinical Trials of Preventive Vaccines (2019) issued by China National Medical Products Administration or other applicable adverse event grading standards referred in the protocol;
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Treatment groupsSee each treatment group below.