In short
Clinical trials are studying VARICELLA VIRUS OKA/MERCK STRAIN, (LIVE, ATTENUATED) PRODUCED IN HUMAN DIPLOID (MRC-5) CELLS in healthy children and in combined vaccine studies. These trials mainly look at immune response, safety, and how the vaccine compares with marketed chickenpox or MMRV vaccines. Most studies involve children 12 to 15 months old, with one study in children 4 to 6 years old.
Key points
- Clinical trials of VARICELLA VIRUS OKA/MERCK STRAIN, (LIVE, ATTENUATED) PRODUCED IN HUMAN DIPLOID (MRC-5) CELLS are focused on chickenpox prevention in children. Most studies are Phase 3 trials in healthy children aged 12 to 15 months, while one completed Phase 2 study included children aged 4 to 6 years. The trials look at immune response, safety, and how the vaccine compares with other varicella or combined MMRV vaccines. Some studies also test different manufacturing lots or different ways of giving the vaccine. The main measurements are seroresponse, antibody levels, and safety events such as local reactions, fever, rash, and serious adverse events.
Trial overview
The trials in this set study VARICELLA VIRUS OKA/MERCK STRAIN, (LIVE, ATTENUATED) PRODUCED IN HUMAN DIPLOID (MRC-5) CELLS for prevention of varicella, which is chickenpox.
Most studies are Phase 3 trials, which are larger studies used to compare vaccines and confirm immune response and safety.
One completed study is Phase 2 and looked at a combined measles, mumps, rubella, and chickenpox vaccine in healthy children 4 to 6 years old.
Who can participate
The main target group is healthy children 12 to 15 months of age.
One study also included healthy children 4 to 6 years of age who were studied for prevention of measles, mumps, rubella, and varicella infections.
The trials focus on children rather than adults, and they are designed to see how the vaccine performs in age groups where routine childhood vaccination is important.
What is measured in the studies
The main outcomes are immune response measures, such as seroresponse and antibody levels against varicella-zoster virus (VZV) glycoprotein E, often called gE.
Several studies measure results at Day 43, which is about 43 days after the second dose or after vaccination, depending on the study.
The safety study tracks local reactions at the injection site, systemic events such as fever, rash, any unsolicited adverse events, medically attended adverse events, and serious adverse events.
One study also looks at geometric mean concentration (GMC), which is a way to describe the average level of antibodies in the blood.
Trial designs and comparisons
Some studies compare investigational varicella vaccine with VARIVAX, a marketed varicella vaccine used as the reference group in the trial data.
One study compares different manufacturing lots to check consistency, meaning the vaccine should perform similarly across batches made in the same process.
One trial studies the vaccine given with MMR vaccine and, if needed, with PCV, while another trial studies a combined measles, mumps, rubella, and chickenpox vaccine compared with a marketed combined vaccine.
Some trials also compare different ways of giving the vaccine, such as subcutaneous injection, which means under the skin, versus intramuscular injection, which means into the muscle.
Key trials in the data
2024-516635-27-00 was a Phase 3 study in healthy children 3 months after a first dose at 12 to 15 months of age. It was withdrawn and planned to compare immune response and safety after a second dose, with primary outcomes at Day 133, or 43 days after dose 2.
NCT06855160 is an authorised Phase 3 study in healthy children 12 to 15 months of age. It compares intramuscular administration of the investigational chickenpox vaccine with subcutaneous administration of VARIVAX and also evaluates MMR vaccine given by different routes.
NCT06740630 is an authorised Phase 3 study in healthy children 12 to 15 months of age. It checks consistency across 3 manufacturing lots and compares pooled lots with pooled VARIVAX lots for immune response at Day 43.
NCT06693895 is an authorised Phase 3 safety study in healthy children 12 to 15 months of age. It focuses on local and systemic events after vaccination, including fever, rash, and serious adverse events up to study end.
2022-501564-18-00 is a completed Phase 2 study in healthy children 4 to 6 years of age. It studied a combined measles, mumps, rubella, and chickenpox vaccine and measured antibody levels against measles, mumps, rubella, and varicella at Day 43.
Patient glossary
Seroresponse means the blood test shows the body has responded to the vaccine.
Unsolicited adverse events are health problems reported during the study even if the study did not ask about them directly.
Medically attended adverse events are unwanted health problems that lead to medical care.
Non-inferiority means the new vaccine is being tested to show it is not worse than the comparison vaccine by more than a set amount.
VZV stands for varicella-zoster virus, the virus that causes chickenpox.