Table of Contents
- Trial overview
- Who can participate
- What the study measures
- Study design and phase
- Where the trial is being done
- Key terms explained
Trial overview
This study is an interventional clinical trial, which means participants receive a vaccine so researchers can compare results between groups.[1] It is studying YELLOW FEVER VIRUS, STRAIN VYF-247, LIVE against the control vaccine Stamaril in adults with yellow fever.[1]
The trial is authorised and planned for 690 participants.[1] Its brief summary says the main purpose is to show non-inferiority, meaning the new vaccine should work at least nearly as well as the comparison vaccine.[1]
Who can participate
The trial includes adults in Europe and Asia.[1] A main analysis is planned for participants in the EU who are YF-naïve, meaning they have not been vaccinated against yellow fever before.[1]
This focus on YF-naïve people matters because the study wants to see how a first yellow fever vaccine dose works in people without prior yellow fever vaccine exposure.[1]
What the study measures
The main endpoint is the percentage of participants who show seroconversion to yellow fever virus 28 days after vaccination.[1] Seroconversion is defined in the study as a 4-fold increase in neutralizing antibody levels compared with the level before vaccination.[1]
Neutralizing antibodies are immune proteins that can block a virus from infecting cells, so this measurement helps show whether the vaccine triggered a strong immune response.[1]
Study design and phase
This is a Phase 2 trial.[1] Phase 2 studies usually look more closely at whether a vaccine works and continue to evaluate the immune response in a larger group than early-phase studies.
The study compares one dose of YELLOW FEVER VIRUS, STRAIN VYF-247, LIVE with one dose of Stamaril, both given on Day 01 by subcutaneous use, according to the trial summary.[1] The main comparison is the antibody response 28 days after vaccination.[1]
Where the trial is being done
The study is described as being in Europe and Asia.[1] The brief summary specifically highlights the EU group for the main non-inferiority analysis in YF-naïve participants.[1]
Key terms explained
Seroconversion means the blood test shows a clear immune response after vaccination.[1] In this trial, it means antibody levels increased four times or more compared with before the vaccine.[1]
Non-inferiority means the study is checking whether the investigational vaccine is not worse than the comparison vaccine by an important amount.[1] This is a common way to compare vaccines when the goal is to show similar protection.[1]
Neutralizing antibodies are part of the body’s defense system and are measured here to understand the vaccine response.[1] A higher level after vaccination suggests the immune system has reacted to the vaccine.[1]
