Immunogenicity and Safety of Varicella Vaccine, Live in Healthy Vietnamese Children Aged 1~12 Years: A Single-armed Bridging Clinical Trial

This is a single armed, Phase 3 study to assess the immunogenicity and safety of the varicella vaccine manufactured by Sinovac. A total of 300 healthy participants aged 1-12 years will be enrolled. All participants will receive a single dose of varicella vaccine manufactured by Sinovac.

Study Overview

• Status: Not yet recruiting
• Conditions: Varicella Immunisation; Varicella (Chickenpox)
• Intervention / Treatment: Biological: Varicella Vaccine

• Study Type: Interventional
• Enrollment (Estimated): 300
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Pham Thi Van Anh; Phone Number: +84- 915 595 690; Email: phamthivananh.hmu@gmail.com

Study Locations

• Vietnam
  • Hanoi, Vietnam, 100000
    • Hanoi Medical University
    • Contact: Pham Thi Van Anh; Phone Number: +84- 915 595 690; Email: phamthivananh.hmu@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Healthy children aged 1-12 years;

2. Vaccination history:

   • Participants aged 1 year old: no vaccination history with any varicella containing vaccine;
   • Participants aged 2~12 years old: no vaccination history with any varicella containing vaccine, or have received 1 dose of varicella vaccine at least 3 months before enrollment;
3. Participants and/or their legal guardians are able to understand and sign the informed consent/assent voluntarily;
4. Participants are able to comply with the study procedures based on the assessment of the investigator;
5. Participants should provide verifiable identification, to be contacted, and to contact the investigator during the study period.

Exclusion Criteria:

1. Prior history of VZV infection;
2. Have been exposed to VZV at home, day care, school, etc. within 4 weeks before enrollment;
3. Known allergy to vaccines or vaccine ingredients, or serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneurotic edema;
4. Autoimmune diseases, immunodeficiency diseases (including but not limited to systemic lupus erythematosus, ankylosing spondylitis, autoimmune thyroid diseases, asplenia, functional asplenia, and HIV infection);
5. Coagulation disorders (e.g. factor deficiency, platelet disorders), or history of bleeding, hematoma, or bruising following intramuscular injections or venipuncture;
6. Poorly controlled chronic illnesses or history of severe diseases that, including but not limited to cardiovascular diseases, hematological disorders, liver and kidney diseases, digestive system disorders, respiratory diseases, malignancies, and a history of major organ transplantation;
7. Any confirmed or suspected syphilis, hepatitis B or hepatitis C infection;
8. Current or history of severe neurological diseases (epilepsy, convulsions or seizures [excluding history of febrile seizures]) or psychiatric disorders, or presence of a family history of psychiatric disorders;
9. Receipt of ≥14 days of immunosuppressive or other immunomodulatory therapy (prednisone ≥20mg/day, or prednisone ≥2mg/kg/day, or its equivalent), cytotoxic therapy within 180 days prior to screening, or plans for such treatment during the trial;
10. Receipt of blood products or immunoglobulins within 180 days prior to screening, or plans to receive these treatments in the trial;
11. Receipt of other investigational drugs/vaccines within 30 days prior to screening, or plans to receive such drugs or vaccines during the study period;
12. Receipt of attenuated live vaccines or nucleic acid vaccines within 28 days prior to screening, or subunit or inactivated vaccines within 7 days prior to screening;
13. Fever on vaccination day, with axillary temperature >37.2°C pre-vaccination, or vital signs outside normal range, or failure to pass physical examination;
14. Presence of skin injuries, inflammation, ulcers, rashes, scars, or other conditions at the intended injection site that may interfere with drug administration or observation of local reactions;
15. Acute onset of various acute diseases or chronic diseases within the past 7 days, or known or suspected active infections;
16. Any other factors considered by the investigator to make the participant unsuitable for participation in the trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1; Participants aged 1-12 years with no vaccination history of varicella-containing vaccine	Biological: Varicella Vaccine; Varicella vaccine manufactured by Sinovac
Experimental: Group 2; Participants aged 2-12 years have received 1 dose of varicella vaccine	Biological: Varicella Vaccine; Varicella vaccine manufactured by Sinovac

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The seroresponse rate of varicella-zoster virus (VZV) antibodies among susceptible population without varicella immunization history	42 days after vaccination

Secondary Outcome Measures

Outcome Measure	Time Frame
The Geometric Mean Concentration(GMC) of VZV antibodies among susceptible population without varicella immunization history	42 days after vaccination
The Geometric Mean Concentration(GMC) of VZV antibodies in total population	42 days after vaccination
The seropositive rate of VZV antibodies in total population	42 days after vaccination
The geometric mean fold rise (GMFR) of VZV antibodies in total population	42 days after vaccination
The geometric mean fold rise (GMFR) of VZV antibodies among population with varicella immunization history	42 days after vaccination
The geometric mean concentration (GMC) of VZV antibodies among population with varicella immunization history	42 days after vaccination
The seropositive rate of VZV antibodies among population with varicella immunization history	42 days after vaccination

Collaborators and Investigators

• Sponsor: Sinovac (Dalian) Vaccine Technology Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: March 11, 2026
• First Submitted That Met QC Criteria: March 11, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): March 16, 2026
• Last Update Submitted That Met QC Criteria: March 11, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Varicella Zoster Virus Infection; Infections; Virus Diseases; DNA Virus Infections; Herpesviridae Infections; Chickenpox; Biological Products; Complex Mixtures; Vaccines; Viral Vaccines; Herpesvirus Vaccines; Chickenpox Vaccine
• Other Study ID Numbers: PRO-VZV-4009

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No