Exploring Immune Responses After Yellow Fever and Typhoid Vaccinations in Adults Aged 18 to 65

What this Trial Is About

Researchers are exploring a concept called innate immune memory, which may provide broad protection against infections beyond the specific disease targeted by a vaccine. This study focuses on the immune response triggered by a live attenuated vaccine for yellow fever and a subunit vaccine for typhoid, aiming to better understand how these vaccines might train the immune system in a non-specific way. The project is an exploratory clinical investigation conducted by Institut Pasteur. Participants in this study will receive primary immunization against yellow fever and typhoid through two vaccine appointments scheduled 7 days apart. Blood samples will be collected at multiple time points at the start day 0, week 1, week 5, month 3, and month 6 to observe changes in immune cells over time. The study will specifically analyze the immunological profile of peripheral blood mononuclear cells PBMCs before and after vaccination, as well as the response to the TyphimVi4 vaccine. Throughout the study, participants will undergo several blood draws to monitor immune responses across six months. Researchers will evaluate the immune systems activity and memory after vaccination using these blood samples. The study includes adults aged 18 to 65 who require vaccination against yellow fever and typhoid. Safety and health status will be monitored, and participants must attend all scheduled visits, including one month after the typhoid vaccine injection, to complete the study assessments.

Description of the Immune Response to Yellow Fever Vaccination