Study Design and Population: This double-blind, randomized, placebo-controlled, phase 3 trial conducted in Brazil evaluated the efficacy and safety of the Butantan-dengue vaccine (Butantan-DV) in 16,235 healthy participants aged 2–59 years. Participants, who had not previously received a dengue vaccine, were randomly assigned to receive either a single dose of Butantan-DV or a placebo and were followed up for an average of 3.7 years.
Main Findings: The study found that Butantan-DV demonstrated 67.3% efficacy against virologically confirmed dengue (VCD) caused by any dengue virus serotype, with no cases of VCD caused by DENV-3 or DENV-4. The proportions of serious adverse events were similar between the vaccine and placebo groups, indicating that the vaccine was generally well tolerated.
Implications for Practice: The results support the potential of the Butantan-DV vaccine as an effective intervention for preventing symptomatic dengue, particularly from DENV-1 and DENV-2, across a broad age range regardless of dengue serostatus. Continued development and monitoring are warranted to confirm long-term efficacy and safety.