To evaluate the safety and tolerability of different dosages of recombinant zoster vaccine (CHO cell) when administered to adults aged 40 years and older.

30 days After each dose of vaccination

Inclusion Criteria:

• Participants are aged ≥40 years on the day of enrollment and can provide legal identity documents;
• The participant voluntarily agrees to take part in the trial and is capable of fully understanding and signing the informed consent form;
• The participant is able to comply with the requirements specified in the clinical trial protocol.

Exclusion Criteria:

• Axillary body temperature >37.3°C on the day of enrollment*;
• Subjects with a prior history of herpes zoster, or having had close contact with patients with chickenpox/herpes zoster within 30 days prior to enrollment;
• Subjects with previous vaccination history of chickenpox or herpes zoster vaccine;
• Subjects allergic to any component of the investigational vaccine (Varicella-Zoster Virus glycoprotein E, BK-02 adjuvant, dipotassium hydrogen phosphate trihydrate, sodium dihydrogen phosphate monohydrate, sucrose, Polysorbate 80), or with a history of severe hypersensitivity to any drugs or vaccines;
• Confirmed or suspected immunosuppression or immunodeficiency disorders induced by underlying diseases or immunosuppressive/cytotoxic therapies, including but not limited to subjects diagnosed with immunodeficiency diseases, malignant tumors, HIV infection, leukemia, lymphoma, Hodgkin's disease, or compromised immunity resulting from organ and bone marrow transplantation;
• Subjects with asplenia or functional asplenia, or autoimmune diseases such as Hashimoto's thyroiditis, vitiligo, rheumatoid arthritis, ankylosing spondylitis;
• Subjects suffering from severe illnesses or potential severe underlying diseases that may interfere with or prevent trial completion (e.g., pulmonary heart disease, pulmonary edema, uncontrolled hypertension despite medication: for participants aged 40-59 years, systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg; for participants aged ≥60 years, systolic blood pressure ≥150 mmHg and/or diastolic blood pressure ≥100 mmHg, severe hepatic and renal diseases, complicated diabetes mellitus, severe cardiovascular diseases, etc.);
• Subjects presenting with acute illnesses (e.g., acute upper respiratory tract infection accompanied by fever, dyspnea and other symptoms) within 3 days before vaccination, or in acute exacerbation phase of chronic diseases, or receiving antipyretic, analgesic or anti-allergy medications*;
• Subjects who received immunosuppressive therapy within 6 months prior to vaccination or plan to receive such therapy from enrollment through 1 month after completion of full-course immunization (e.g., systemic glucocorticoids administered for ≥14 consecutive days at a daily dose of ≥2 mg/kg or ≥20 mg prednisone or equivalent prednisone dosage; topical steroids including inhalants, nasal sprays, intra-articular injections, eye drops and ointments are excluded); subjects administered long-acting immunomodulatory agents (e.g., infliximab) within 6 months before the first vaccination or scheduled to receive such agents from enrollment to 1 month after full vaccination completion;
• Subjects receiving whole blood, plasma or immunoglobulin transfusion within 3 months prior to vaccination or planning to receive such treatments from enrollment through 1 month after completion of full-course immunization;
• Females of childbearing age planning pregnancy during the trial, or who are pregnant (positive pregnancy test result) or breastfeeding; Subjects with a medical history of thrombocytopenia or other coagulation disorders contraindicating intramuscular injection;
• Subjects with clinically significant abnormal findings in laboratory tests or electrocardiogram confirmed by a clinician before the first vaccine dose;
• Subjects with personal or family history of convulsion, epilepsy, encephalopathy (e.g., cerebral nerve tissue damage caused by congenital cerebral dysplasia, craniocerebral trauma, brain tumor, cerebral hemorrhage, cerebral infarction except lacunar infarction and cerebral infarction without sequelae, intracranial infection, chemical drug poisoning, etc.), psychiatric disorders or other severe neurological diseases;
• Subjects who received live attenuated vaccines within 14 days before vaccination, or recombinant protein vaccines/inactivated vaccines within 7 days before vaccination*;
• Subjects who have used any investigational or unapproved products (drugs, biological products or medical devices) within 3 months prior to vaccination or intend to use such products during the trial period;
• Any other conditions deemed likely to interfere with trial evaluation by the investigator.