Safety and Immunogenicity of the Live-Attenuated Quadrivalent Dengue Vaccine V181 Compared With Butantan-DV Among Healthy Adults in Brazil: A Randomized, Double-Blind, Phase 2 Trial.

BACKGROUND: Dengue is caused by infection with 1 of 4 dengue virus (DENV) serotypes (DENV-1 to DENV-4). V181 and Butantan-Dengue Vaccine (Butantan-DV) are independently developed, single-dose, quadrivalent dengue vaccines based on the same attenuated parental strains. METHODS: In this randomized, double-blind, active comparator-controlled, multisite, phase 2 trial, we compared the safety and immunogenicity of V181 and Butantan-DV in healthy adults in Brazil. The primary immunogenicity objectives were to compare vaccine-induced neutralizing antibody geometric mean titers (GMTs) and seroconversion rates for DENV-1 to DENV-4 at day 28 postvaccination. The primary and secondary safety objectives, respectively, were to assess vaccine-related serious adverse events and the proportion of participants experiencing solicited adverse events through day 28 postvaccination. RESULTS: Overall, 1364 participants were assigned (1:1) to receive V181 (n = 682) or Butantan-DV (n = 682). At day 28 postvaccination, V181 induced a noninferior immune response to Butantan-DV for DENV-1 and DENV-2 but not DENV-3 and DENV-4, as measured using GMT ratios. Noninferiority was established for all DENV serotypes based on seroconversion rates. Most participants developed a trivalent or tetravalent neutralizing antibody response. Vaccine viremia was detected for each DENV serotype. V181 and Butantan-DV were generally well tolerated. CONCLUSIONS: V181 was immunogenic in adults, and while immunogenicity was noninferior to Butantan-DV for DENV-1 and DENV-2, seroconversion rates were noninferior for DENV-1 to DENV-4. The safety profile of V181 is comparable to that of Butantan-DV and supports its continued evaluation as a single-dose quadrivalent vaccine for dengue prevention. CLINICAL TRIALS REGISTRATION: NCT05710224.