In short
Clinical trials of VARICELLA VIRUS OKA/MERCK STRAIN (LIVE, ATTENUATED) are studying chickenpox vaccine use in healthy children aged 12 to 15 months. These studies look at safety, immune response, and how different vaccine lots compare. Some trials also assess a second dose given later.
Key points
- Clinical trials of VARICELLA VIRUS OKA/MERCK STRAIN (LIVE, ATTENUATED) are studying a chickenpox vaccine in healthy children aged 12 to 15 months. The listed studies are all Phase 3 trials, which means they are testing the vaccine in larger groups. One trial focuses on immune response and lot consistency, another focuses on safety when given with other childhood vaccines, and a third looked at immune response after a second dose. The studies measure antibody response using seroresponse and geometric mean concentration. Safety measurements include local reactions, fever, rash, other side effects, and serious medical events.
Overview of the trials
These trials study VARICELLA VIRUS OKA/MERCK STRAIN (LIVE, ATTENUATED) in children and compare it with another varicella vaccine listed in the trial records as VARIVAX. The studies are about varicella, which means chickenpox.
All three trials are Phase 3 studies. Phase 3 trials usually involve larger groups and are used to check safety and immune response in a more complete way.
Main studies and what they tested
NCT06740630 studied the immune response and safety of an investigational chickenpox vaccine in healthy children 12 to 15 months of age. The main goal was to show consistency across three manufacturing lots and to compare the pooled lots with the comparator vaccine group.
NCT06693895 studied safety of the investigational chickenpox vaccine in healthy children 12 to 15 months of age. This trial also looked at safety and reactogenicity, which means the short-term reactions seen after vaccination, when the vaccine was given with MMR vaccine, HAV vaccine, and, if applicable, PCV.
2024-516635-27-00 studied the immune response and safety of a second dose given 3 months after the first dose in healthy children who first received the vaccine at 12 to 15 months of age. This study was withdrawn.
Who could take part
The main target group in these trials was healthy children 12 to 15 months of age.
One study also included children who had already received a first dose and then returned for a second dose 3 months later.
What the trials measured
The immune response studies measured seroresponse, which means whether the child made a clear antibody response after vaccination.
They also measured Geometric Mean Concentration (GMC) of anti-VZV gE IgG, which is a way to show the average level of specific antibodies in the group.
The safety trial measured local reactions at the injection site, systemic events such as fever, rash, unsolicited adverse events, medically attended adverse events, and serious adverse events.
The time points in the records were important too. Immune response was checked at Day 43 in the first study, while the second-dose study measured outcomes at Day 133, which is 43 days after dose 2.
Trial phases and status
All three studies were listed as Phase 3 trials, but their status was not the same.
- NCT06740630 was authorised and had 1,738 planned participants.
- NCT06693895 was authorised and had 770 planned participants.
- 2024-516635-27-00 was withdrawn and had 600 planned participants.
Key points for patients
These trials are not about treating sick children with chickenpox. They are about studying a vaccine in healthy young children to see how well the immune system responds and how safe the vaccine is.
The main focus is on antibody response, safety after vaccination, and comparison between vaccine lots or doses. This helps researchers understand whether the vaccine performs consistently across different batches and dosing schedules.