Table of contents
- Trial overview
- Who is being studied
- Study design and comparison
- Main endpoint and what it means
- Trial status and enrollment
Trial overview
The available clinical trial is titled “Study on an Investigational Yellow Fever Vaccine Compared with Stamaril in Adults in Europe and Asia.”[1] It is an interventional study, which means participants receive a vaccine so researchers can measure the effect.[1] The condition being studied is yellow fever.[1]
Who is being studied
This trial is in adults in Europe and Asia.[1] The study focuses on YF-naïve participants, meaning people who have not been vaccinated against yellow fever before.[1] This helps the researchers see the vaccine response in people starting without prior yellow fever vaccination.[1]
Study design and comparison
The study is in Phase 2, a stage that usually looks at how well a treatment works while continuing to assess its effects in a larger group of people.[1] YELLOW FEVER VIRUS, STRAIN VYF-247, LIVE is being compared with Stamaril, which is the control vaccine in this trial.[1] The brief summary says the study aims to show non-inferiority of the antibody response, meaning the investigational vaccine is being tested to see whether its immune response is not meaningfully worse than the control vaccine.[1]
Main endpoint and what it means
The primary outcome is the percentage of participants in the EU who have seroconversion to yellow fever virus in the YF-naïve population.[1] In this study, seroconversion is defined as a 4-fold increase in neutralizing antibody levels compared with the level before vaccination.[1] The main time point is 28 days after vaccine administration.[1]
For patients, this endpoint is a way to check whether the body has made a clear immune response after vaccination.[1] Neutralizing antibodies are important because they are used in the trial as a blood marker of vaccine response.[1]
Trial status and enrollment
The trial status is Authorised.[1] The planned enrollment is 690 participants.[1] This number gives the researchers enough people to compare the immune response between the investigational vaccine and the control vaccine.[1]



