1. In this randomized controlled trial, the Butantan-Dengue Vaccine (Butantan-DV) was effective in the prevention of symptomatic, virologically confirmed dengue after two years, regardless of baseline serostatus. 2. Butantan-DV was effective against DENV-1 and DENV-2 serotypes across all age groups. Evidence Rating Level: 2 (Good) Study Rundown: Dengue is a mosquito-borne viral illness that can result in