Study on the Immune Response and Safety of a Second Dose of Investigational Varicella Vaccine (GSKVX000000025896) Compared to Varicella Virus Oka/Merck Strain in Healthy Children

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What is this study about?

This clinical trial is focused on studying the immune response and safety of a second dose of an investigational vaccine for chickenpox, also known as varicella. The study involves healthy children who have already received a first dose of the vaccine between the ages of 12 to 15 months. The investigational vaccine is being compared to an existing vaccine called VARIVAX®, which contains a live, weakened form of the varicella virus. The investigational vaccine is identified by the code name GSKVx000000061721.

The purpose of the study is to evaluate how well the investigational vaccine works in generating an immune response compared to the existing vaccine. The study will involve giving a second dose of either the investigational vaccine or the existing vaccine to the children three months after their first dose. The vaccines are given as an injection under the skin, known as a subcutaneous injection. The study will monitor the children’s immune response to the varicella zoster virus and any side effects that may occur after receiving the second dose.

Throughout the study, researchers will observe the children for any reactions at the injection site and any general symptoms, such as fever. The study will also track any unexpected health issues that may arise. The goal is to ensure that the investigational vaccine is as effective and safe as the existing vaccine in protecting against chickenpox. The study is expected to continue until the end of 2026.

1 joining the study

Upon joining the study, the participant’s parent or legally acceptable representative must provide written or witnessed consent. This consent is necessary before any study-specific procedures can begin.

The participant must be healthy, as determined by a medical history review and clinical examination.

2 first dose administration

The first dose of the investigational varicella vaccine is administered to the participant. This vaccine is given as a suspension for injection under the skin, known as a subcutaneous injection.

The participant must be between 12 to 15 months of age at the time of this first dose.

3 monitoring after first dose

After the first dose, the participant is monitored for any solicited administration site events from Day 1 to Day 4.

Monitoring for solicited systemic events, such as fever, occurs from Day 1 to Day 22.

Any unsolicited adverse events are recorded from Day 1 to Day 43.

4 second dose administration

Three months after the first dose, the second dose of the investigational varicella vaccine is administered. This is also given as a suspension for injection under the skin.

The second dose is crucial for evaluating the immune response and safety of the vaccine.

5 monitoring after second dose

Following the second dose, monitoring for solicited administration site events occurs from Day 91 to Day 94.

Monitoring for solicited systemic events, including fever, takes place from Day 91 to Day 112.

Any unsolicited adverse events are recorded from Day 91 to Day 133.

6 final evaluation

The primary evaluation of the immune response is conducted 43 days after the second dose, on Day 133.

The study continues to monitor for any medically attended adverse events and serious adverse events until the end of the study on Day 271.

Who Can Join the Study?

The participant’s parent(s) or legally acceptable representative(s) must be able and willing to follow the study requirements, according to the study investigator.
Written or witnessed/thumb-printed informed consent must be obtained from the participant’s parent(s) or legally acceptable representative(s) before any study-specific procedures are performed.
The participant must be healthy, as determined by medical history and a clinical examination before joining the study.
The participant must be a male or female between 12 to 15 months of age. This means from the day they turn 1 year old until the day before they turn 16 months old, at the time of the first study intervention.
For children in countries where the Pneumococcal Conjugate Vaccine (PCV) is recommended at 12 to 15 months of age as part of the national immunization schedule and provided as part of the study interventions: The participant must have previously received the primary series of PCV in the first year of life, with the last dose given at least 60 days before entering the study.

Who Cannot Join the Study?

Having a current or past infection with Varicella (also known as chickenpox).
Receiving any other vaccines within 4 weeks before the first dose of the study vaccine.
Having a known allergy to any component of the study vaccine.
Having a weakened immune system, which means your body has a harder time fighting infections.
Being pregnant or planning to become pregnant during the study period.
Breastfeeding during the study period.
Participating in another clinical trial at the same time.
Having a history of severe reactions to vaccines in the past.
Having any other medical condition that the study doctors think might make it unsafe for you to participate.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Oslo Universitetssykehus HF	Oslo	Norway

Other Sites

Site Name	City	Country
Helse Stavanger HF	Stavanger	Norway
Aalborg University Hospital	Aalborg	Denmark
Region Midtjylland	Aarhus	Denmark
Regionshospital Nordjylland	Hjørring	Denmark
Hkfxrr Hfqkhegh	Herlev	Denmark
Hjxps Bnluwz Ha	Bergen	Norway

Trial status

Country	Status	Recruitment Start
Denmark	Not yet recruiting	15.07.2025
Norway	Not yet recruiting	15.07.2025

Trial locations

Investigated drugs:

Investigational Varicella Vaccine (VNS) is a new vaccine being tested to see how well it works in protecting against chickenpox. Chickenpox is a common childhood illness caused by the varicella-zoster virus, which can cause an itchy rash and fever. This vaccine is given to children to help their bodies build up defenses against the virus, so they are less likely to get sick if they are exposed to it. In this study, the vaccine is given as a second dose to see if it helps improve the immune response compared to the standard vaccine.

Varivax is an existing vaccine that is already used to protect children against chickenpox. It works by helping the body develop immunity to the varicella-zoster virus, which causes chickenpox. In this study, Varivax is used as a comparison to the new investigational vaccine to see if the new vaccine is as effective or better in boosting the immune system’s response to the virus when given as a second dose.

Investigated diseases:

Varicella

Varicella – Varicella, commonly known as chickenpox, is a highly contagious viral infection caused by the varicella-zoster virus. It typically begins with a fever, fatigue, and a characteristic itchy rash that progresses to fluid-filled blisters. These blisters eventually crust over and heal. The rash usually starts on the face, chest, and back before spreading to the rest of the body. The disease is more common in children, but it can occur at any age. After the initial infection, the virus can remain dormant in the body and may reactivate later in life as shingles.

Trial ID:

2024-516635-27-00

Protocol code:

214002 (VNS 20-004)

Trial Phase:

Therapeutic confirmatory (Phase III)

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Study on the Immune Response and Safety of a Second Dose of Investigational Varicella Vaccine (GSKVX000000025896) Compared to Varicella Virus Oka/Merck Strain in Healthy Children

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?