Cai Lay

Researchers are evaluating the safety, immune response, and effectiveness of the V181 dengue vaccine in healthy children aged 2 to 17 years. The study aims to show that V181 is safe, well tolerated, and reduces the frequency of dengue infections caused by any of the four dengue virus types, regardless of whether the child had previous exposure to dengue before vaccination. This is a phase 3, randomized, double-blind, placebo-controlled trial involving healthy participants within this age range. Participants will be randomly assigned to receive either a single 0.5 mL subcutaneous dose of the V181 vaccine or a placebo on Day 1. A subset of about 3,600 participants will be closely followed for immune response and safety for 28 days after vaccination. From this group, around 620 participants will be randomly selected to have their long-term immune response evaluated at selected times for up to 5 years after vaccination. Throughout the study, children will undergo medical history reviews and physical exams to confirm health status. Safety will be monitored by recording adverse events, including those requiring medical attention up to 6 months post-vaccination and serious events up to 5 years. The study also tracks injection site reactions and systemic side effects shortly after vaccination, and measures vaccine effectiveness by monitoring dengue infection rates up to 3 years after vaccination. Immune response tests will be done at planned intervals to assess how well the vaccine works over time.