Using AS01 Adjuvant to Improve Immune Response in Adults Aged 21 to 59 Through Trained Immunity

What this Trial Is About

Researchers are studying how the immune system weakens with age, making older adults more prone to infections and less responsive to vaccines. This trial focuses on AS01, an ingredient used in vaccines like the shingles vaccine, which may act like a fitness trainer for the immune system. The study aims to see if AS01 alone can boost and train the immune system in healthy adults aged 21 to 59, how long this effect lasts, and whether it helps fight other infections better. Participants receive a single intramuscular dose of either AS01 or a placebo on the first day. Then, they are randomly assigned to get a live-attenuated yellow fever vaccine (YF17D) either one month or three months later. There are four groups in total: AS01 plus yellow fever vaccine at 1 month, AS01 plus yellow fever vaccine at 3 months, placebo plus yellow fever vaccine at 1 month, and placebo plus yellow fever vaccine at 3 months. This design helps researchers study immune responses over approximately 2 to 4 months. Throughout the study, participants will have blood samples taken at multiple timepoints to measure immune changes, including gene and epigenetic markers, and immune responses to the yellow fever vaccine. Researchers will analyze how well the immune system controls the viral challenge and monitor safety, including common injection site reactions and systemic symptoms. The total participation time depends on the assigned group and lasts up to about 3 months.

Improving Vaccine Protection for Adults