Phase IIIb Clinical Trial to Evaluate Lot-to-lot Consistency of Sinovac Rabies Vaccine

Lot-to-lot Consistency and Safety of Rabies Vaccine (Vero Cell) for Human Use, Freeze-dried in Healthy Individuals Aged 18-45 Years: A Randomized, Double-Blind Phase IIIb Clinical Trial

To evaluate immunogenicity consistency between three consecutive batches of commercial-scale productions for Sinovac Rabies vaccine

This clinical trial employed a randomized, double-blind design, enrolling a total of 912 participants aged 18 to 45 years. The investigational vaccine was the serum-free rabies vaccine produced by Sinovac. Eligible participants were enrolled and randomized in a 1:1:1 ratio into Trial group 1, Trial group 2, and Trial group 3, with 304 participants in each group. They received vaccination according to the Essen regimen (1-1-1-1-1) on days 0, 3, 7, 14, and 28, for a total of 5 doses of tjhree commercially scaled batches of the rabies vaccine.

Blood samples will be collection at baseline before the first dose of immunization (D0), 14 days after the first dose (D14, before the third vaccination), and 14 days after the full course of immunization (D42), as well as 3, 6, and 12 months after the full course of immunization. All participants were required to complete immediate reaction observation within 30 minutes after each vaccine dose, and adverse events and serious adverse events were collected from the first dose of baseline immunization vaccination until 30 days after the last dose.

Inclusion Criteria:

1. Participants are able to understand and voluntarily sign the Informed Consent Form;
2. Able to provide legal identity documents;
3. Age 18 to 45 years;
4. Stable health status (defined as stable underlying disease status within 3 months prior to enrollment, i.e., no change in original treatment or hospitalization due to disorder aggravation);
5. Female participants of childbearing potential must voluntarily adopt effective contraception measures from the signing of the Informed Consent Form until 2 months after the last dose of the investigational Vaccine in the primary immunization series, and have no plans to donate eggs; male participants have no plans to donate sperm; female participants of childbearing potential must also have adopted effective contraception measures within 2 weeks prior to Enrollment.

Exclusion Criteria:

1. For subjects with pyrexia on the scheduled vaccination day, axillary temperature >37.3℃ before vaccination;
2. Previous use of anti-Rabies Passive immunization preparations (including but not limited to equine-derived Immunoglobulin ERIG, human-derived Immunoglobulins HRIG, and rabies monoclonal antibody preparations, etc.) or previous Vaccination with human Rabies Vaccine;
3. Individuals with mammalian animal bites/scratches (e.g., dog/cat) and broken skin (i.e., Category II or higher exposure) within the past year.;
4. Female participants who are lactating or pregnant (including those with a positive urine pregnancy test).
5. Known allergy to any component of the trial Vaccine, or a history of severe allergies (such as anaphylactic shock, allergic laryngeal edema, allergic purpura, severe urticarial rash, dyspnea, angioneurotic edema, etc.);
6. Presence of autoimmune diseases, immunodeficiency diseases (including but not limited to systemic lupus erythematosus, ankylosing spondylitis, asplenia, functional asplenia, splenectomy);
7. Poorly controlled chronic diseases or history of severe diseases, including but not limited to cardiovascular disorders (e.g., uncontrolled hypertension: systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg), metabolic diseases (e.g., poorly controlled diabetes), hematological diseases, liver and kidney diseases, digestive system diseases, respiratory system disorders, history of major organ transplantation, malignant neoplasms within the past five years, or any other diseases or physiological conditions that the investigator believes may interfere with the trial results.
8. History of encephalopathy with significant recovered with sequelae or dysfunction, or current encephalopathy (e.g., congenital cerebral dysgenesis, brain trauma, brain tumor, cerebral hemorrhage, cerebral infarct, brain infection, chemical drug poisoning, etc., causing brain nerve tissue injury); history of convulsions, epilepsy, mental illness or family history of mental illness, or other serious neurological diseases;
9. Presence of physician-diagnosed coagulation abnormalities (e.g., coagulation factor deficiency, coagulation disorders, platelet abnormalities);
10. Systemic immunosuppressive agents or other immunomodulatory therapy for ≥14 days within the past 6 months (prednisone ≥20 mg/day or ≥2 mg/(kg·day), or equivalent), cytotoxic therapy, or planned receipt of such therapy during the study period;
11. Received Immunoglobulins or other blood products within 3 months prior to receiving the investigational Vaccine, or plans to receive such treatment during the study period;
12. Received other Study Drug or Vaccine within the past 30 days, or plans to receive such drug or Vaccine during the study period;
13. Within 14 days prior to receiving the investigational vaccine, vaccination with a live attenuated vaccine, or within 7 days, vaccination with subunit, inactivated, or other types of vaccines.
14. Currently participating in other Vaccine or drug Clinical Studies, or planning to participate in other Clinical Trials during the study period;
15. Subjects with skin injuries, inflammation, ulcers, skin rash, or scars at the Vaccination site that may interfere with dosing or the observation of local reactions.
16. Within 3 days prior to vaccination, any acute disease or acute exacerbation of a chronic disease, or known or suspected active infection;
17. Based on the Investigator's judgment, the participant has any other discomfort or factors suitable for participating in the clinical trial.