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Second Dose of Varicella Vaccine in Healthy Children | Clinical Trials | Clareo Health

RECRUITINGPHASE3

Second Dose of Varicella Vaccine in Healthy Children

Immunogenicity and Safety of the Second Dose of Varicella Vaccine in Healthy Children: An Open-label Study

NCT07475000•Sinovac (Dalian) Vaccine Technology Co., Ltd.

Summary

This study aim to assess the immunogenicity and safety of interchangeable administration of the second dose of varicella vaccine. A total of 300 healthy participants aged 15 months - 12 years will be enrolled. Written informed consent form will be obtained from participants' parents or legally acceptable representatives (and assents will be obtained from participants aged above 9 years old and written consent forms will be prepared and consent will be obtained in writing if possible from the participants aged 3-8 years old.) before enrollment. Participants will be assigned to 5 groups according to the brand of first dose varicella vaccine they received at the age of 12 months. All participants will receive the second dose of varicella vaccine manufactured by Sinovac. The duration of individual participation from enrollment to the last onsite visit will be a maximum of 42 days. The end of study is considered the completion of the last visit for the last participant in this study. Blood samples (2.5 - 3.0ml per time) for immunogenicity assessment will be collected. The blood samples will be collected before vaccination and 42 days after vaccination.

Eligibility

Age

1 - 12 years

Sex

ALL

Healthy Volunteers

Yes

Inclusion Criteria

•1. Healthy children aged 15 months to 12 years.
•2. Have received one dose of varicella vaccine at 12 months of age in Turkey (verified by vaccination card or official electronic immunization record).
•3. Written informed consent obtained from parent(s) or legally authorized representative(s); assent obtained from children as applicable according to local regulations.
•4. Able to comply with study procedures, as assessed by the investigator.
•5. Able to provide verifiable identification and be contacted for study follow-up during the study period.

Exclusion Criteria

•1. History of varicella-zoster virus (VZV) infection (based on parental report or medical record).
•2. Known exposure to VZV within 4 weeks prior to screening.
•3. Receipt of more than one dose of varicella vaccine.
•4. Interval between first dose of varicella vaccine and enrollment less than 3 months.
•5. Known allergy to any vaccine component or history of severe allergic reaction to any vaccine (e.g., urticaria, dyspnea, angioedema).
•6. Known or suspected immunodeficiency or autoimmune disease (including but not limited to systemic lupus erythematosus, ankylosing spondylitis, autoimmune thyroid disease, asplenia, functional asplenia, or HIV infection).
•7. Poorly controlled chronic disease or history of severe systemic disease.
•8. Current or history of severe neurological disorders (e.g., epilepsy, convulsions or seizures excluding simple febrile seizures) or psychiatric disorders.
•9. Receipt of ≥14 days of immunosuppressive or immunomodulatory therapy (e.g., prednisone ≥20 mg/day or ≥2 mg/kg/day or equivalent), or cytotoxic therapy within 180 days prior to screening, or planned use during the study period.
•10. Receipt of blood products or immunoglobulins within 180 days prior to screening, or planned receipt during the study period.
+6 more criteria

Locations (5)

Akdeniz University Health, Research and Application Center (Hospital), Department of Child Health and Diseases, Department of Social Pediatrics

Akdeniz, Turkey (Türkiye)

Ankara Bilkent City Hospital, Pediatrics and Pediatric Infectious Diseases Clinic

Ankara, Turkey (Türkiye)

Hacettepe University Hospitals, Department of Pediatrics, Department of Social Pediatrics

Ankara, Turkey (Türkiye)

REPUBLIC of TURKEY MINISTRY of HEALTH ANKARA BILKENT CITY HOSPITAL

Ankara, Turkey (Türkiye)

Ege University Hospital (Application and Research Center) Department of Child Health and Diseases

Ege, Turkey (Türkiye)

Key Dates

Start Date

January 28, 2026

Primary Completion Date

July 15, 2026

Completion Date

November 15, 2026

Last Updated

March 16, 2026

Enrollment

300

ESTIMATED participants

Conditions

Varicella (Chickenpox)Varicella Immunisation

Interventions

PROVARIX

BIOLOGICAL

Study of Live Attenuated Varicella Vaccine Co-administered with MMR Vaccine or DTaP Vaccine

NCT06891872

Varicella (chickenpox)MMR Vaccine+1 more

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COMPLETED

The Effectiveness of Varicella Vaccination in Children in Germany

NCT00679796

Varicella (Chickenpox)Chickenpox Vaccines

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Data Source & Attribution

This clinical trial information is sourced from ClinicalTrials.gov, a service of the U.S. National Institutes of Health.

ClinicalTrials.gov last update: March 16, 2026Data synced to Clareo: March 29, 2026

Modifications: This data has been reformatted for display purposes. Eligibility criteria have been parsed into inclusion/exclusion sections. Location data has been geocoded to enable distance-based search. For the authoritative and most current information, please visit ClinicalTrials.gov.

Neither the United States Government nor Clareo Health make any warranties regarding the data. Check ClinicalTrials.gov frequently for updates.

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