A Study to Evaluate the Safety, Tolerability, and Immunogenicity of a Recombinant Herpes Zoster Vaccine

1. Male or female subjects ≥ 40 years of age;
2. The subject can and fully understand the trial procedures and voluntarily sign the ICF;
3. The subject is in a healthy state or has stable underlying diseases according to investigator's assessment based on medical history and related physical examination results;
4. The subject can comply with the requirements of the protocol;
5. The axillary temperature of the subject is \< 37.0℃ on the day of enrollment;
6. Fertile men and women with childbearing potential voluntarily agree to take effective contraceptive measures from the first vaccination to at least 90 days after the last dose of study vaccines.

Exclusion Criteria:

1. History of herpes zoster before enrollment, or close contact with a varicella/herpes zoster patient within 30 days prior to enrollment;
2. Previous vaccination against herpes zoster and varicella (including vaccines that have been registered or under clinical research);
3. Allergic to any component of the study vaccine, or history of severe allergy to any vaccination, such as anaphylactic shock, allergic laryngeal edema, anaphylactoid purpura, thrombocytopenic purpura, local allergic necrosis reaction, angioneurotic edema, etc.
4. History or family history of convulsions, epilepsy, and psychiatric disorders;
5. Suffering from serious chronic diseases or in the active stage of chronic diseases, which are evaluated by the investigator to affect the trial observation, including but not limited to myocardial infarction, severe arrhythmia, unstable angina, hypertension that cannot be controlled after drug treatment (subjects 40-59 years of age have systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, and subjects ≥60 years of age have systolic blood pressure >160 mmHg and/or diastolic blood pressure >100 mmHg), diabetes with severe complications, cancer or precancerous lesions, and other serious cerebrovascular diseases, heart disease, respiratory diseases, liver and kidney diseases, and thyroid diseases;
6. Primary or secondary immunosuppressive condition, or diagnosed with primary or acquired immunodeficiency disease, human immunodeficiency virus (HIV) infection, etc.
7. History of thrombocytopenia or other coagulation disorders, which may cause contraindications for intramuscular injection and venous blood collection;
8. Fever (axillary temperature ≥37.3℃) within 3 days before enrollment or systemic antibiotic or antiviral treatment within 7 days;
9. Use of antipyretic analgesics or other drugs with antipyretic and analgesic effects, such as acetaminophen and ibuprofen, within 72 h before vaccination.
10. Abnormal laboratory test (blood routine, blood biochemistry, urine routine) results that are outside the reference range and clinically significant (only apply to Phase I);
11. Those who are pregnant (positive urine pregnancy test) or breast-feeding, or those who plan to become pregnant during the study period;
12. Long-term or high-dose corticosteroid therapy (duration ≥15 days, or dose ≥1 mg/kg/ day of prednisone or equivalent doses of other corticosteroids), or other immunosuppressive and cytotoxic therapy within 90 days prior to vaccination. Short-term or topical use (such as ointments, eye drops, inhalants, intra-articular medications or nasal sprays) of glucocorticoids is permitted;
13. Vaccination with non-attenuated vaccines within 14 days before the first dose of study vaccines, or with live-attenuated vaccines within 28 days before the first dose of study vaccines;
14. Participation in other clinical trials (drug or vaccine) within 30 days preceding the first dose of study vaccines or planning to participate in other clinical trials before this clinical study is completed;
15. Asplenia or functional asplenia;
16. Those who are known to have been diagnosed or currently have an infectious disease, including hepatitis B, hepatitis C, syphilis or AIDS;
17. Those who have any acute illness or acute onset of chronic illness within 72 hours before the first dose of vaccination;
18. Those who have received blood or blood-related products, including immunoglobulins, within 3 months before the first dose of vaccination, or have planned to use them during the study period;
19. Subjects deemed by the investigator to have other conditions that render them ineligible to participate in this study, which include but are not limited to those who are incapable of participating in follow-up visits based on the protocol.