Tricou V, Sáez-Llorens X, Yu D, et al. - In light of an existing unmet clinical requirement for an effective tetravalent dengue vaccine suitable for all age groups, irrespective of serostatus, researchers undertook a large, phase 2, double-blind, placebo-controlled trial to evaluate the immunogenicity as well as the safety of three different dose schedules of a tetravalent dengue vaccine (TAK-003) over a 48-month span among children residing in dengue-endemic countries. This inquiry was performed at three sites in the Dominican Republic, Panama, and the Philippines. Experts employed an interactive web response system with stratification by age, to randomly allocate healthy participants aged 2–17 years to receive either a two-dose primary series (days 1 and 91), one primary dose (day 1), one primary dose plus booster (days 1 and 365), or placebo. Findings revealed that antibody responses against all four serotypes were evoked by TAK-003, which were shown to persist to 48 months after vaccination, irrespective of baseline serostatus. There were no crucial safety risks. A long-term decrease in risk of symptomatic dengue virus disease was evident in vaccinees. This work affords a long-term safety database as well as support evaluation of the vaccine in the ongoing phase 3 efficacy study.