Immunogenicity and Safety of SYS6017 in the Participants Aged 40 Years and Above

A Randomized, Blinded, Placebo- and Active-Controlled, Adaptive Phase 2 Study to Evaluate the Immunogenicity and Safety of SYS6017 (a Herpes Zoster mRNA Vaccine) in Healthy Participants Aged 40 Years and Above

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".

Inclusion Criteria:

• 1. Individuals aged 40 years or older;
• 2. Able to understand the study procedures, comply with the protocol requirements to attend all the scheduled visits, voluntarily consent to participate in the study, and sign the informed consent form;
• 3. Is physically eligible at the discretion of investigators based on medical history inquiry and physical examination; For participants with chronic underlying diseases (e.g., diabetes mellitus, hypertension, hyperlipidemia and other chronic conditions), they may be enrolled if their conditions have been well controlled within 3 months prior to enrollment in this study (i.e., additional medical interventions or major adjustments to treatments are not required);
• 4. For female participants of childbearing potential: No sexual activity or effective contraceptive methods were used within one menstrual cycle before enrollment; No pregnancy plans and agree to adopt effective contraceptive methods within 8 months after enrollment.

Exclusion Criteria:

• 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. History of allergy to any component of the investigational vaccine; or history of severe allergic reactions to vaccines or medications (including but not limited to anaphylaxis, allergic laryngeal edema, Henoch-Schönlein purpura, thrombocytopenic purpura, or Arthus reaction);
• 5. History of myocarditis, pericarditis, or idiopathic cardiomyopathy, or any condition that could increases the risk of myocarditis or pericarditis
• 6. History of demyelinating diseases, including but not limited to Guillain-Barré syndrome, multiple sclerosis, ophthalmoneuromyelitis, acute disseminated encephalomyelitis, etc.;
• 7. Current epilepsy or convulsion, severe neurological or psychiatric disorders;
• 8. Have contraindications to intramuscular injection, e.g., diagnosed thrombocytopenia, any coagulation disorders, or ongoing treatment with anticoagulants, etc.;
• 9. Active malignant tumor, malignant tumor without adequate treatment, malignant tumor with a potential risk of recurrence during the study;
• 10. Active, unstable, severe or uncontrolled cardiovascular and cerebrovascular diseases, thrombotic diseases, blood and lymphatic system diseases, liver and kidney diseases, respiratory diseases, metabolic diseases, musculoskeletal diseases, autoimmune diseases, etc;
• 11. History of diagnosed immunocompromise or immunosuppression, congenital or functional asplenia, or splenectomy before enrollment;
• 12. Long-term (defined as more than 14 consecutive days) systemic use of immunosuppressants, immunostimulants, or other immunomodulatory drugs (e.g., corticosteroids at a dose of ≥ 20 mg/day prednisone or equivalent) within 6 months prior to enrollment; however, inhaled and topical corticosteroids are permitted; or planned administration of the aforementioned agents during the study period;
• 13. Administration of whole blood, plasma, serum, immunoglobulin, or monoclonal antibodies within 3 months prior to enrollment, or planned administration of the aforementioned products during the study period;
• 14. Blood donation or blood loss ≥ 450 mL within one month before enrollment, or planning to donate blood during the study;
• 15. Vaccination with any other vaccines within 30 days prior to enrollment, or planned vaccination with any other vaccines within 30 days after the last dose of the study vaccine;
• 16. Current participation in or planned participation in other clinical trials during the study period;
• 17. For female participants of childbearing potential: positive pregnancy test result prior to enrollment, current pregnancy or lactation, or planned pregnancy within 8 months after enrollment;
• 18. Unable to comply with the study procedures and requirements, or presence of other conditions that make the participant inappropriate for this clinical trial, as judged by the investigators.