Phase II, Step-wise, Randomized, Double-blind, Controlled Clinical Trial for Safety and Immunogenicity Evaluation of a Lyophilized Formulation of Dengue 1,2,3,4 (Attenuated) Vaccine in Healthy Adults

This is a phase II step-wise, randomized, multicenter, double-blind and controlled clinical trial to evaluate the safety and immunogenicity of an attenuated tetravalent lyophilized dengue vaccine manufactured by Butantan Institute. A total of 300 volunteers will be recruited including men and no pregnant/breastfeeding women between 18 and 59 years of age complete, with and without previous exposure to dengue that will be randomized into Step A and Step B. Step A will include 50 volunteers with no previous exposure and they will be randomly assigned to receive one dose of either the lyophilized formulation (Butantan), or the liquid formulation (TetraVax-DV Vaccine - Admixture TV003 developed by NIH/NIAID and produced and formulated at Butantan according the NIH-Protocol), or the placebo. A second dose will be administered six months after the first vaccination as part of an exploratory assessment. Step B will include 250 participants(50 without previous exposure to dengue,and 200 with previous exposure to dengue) who will be randomly assigned to receive one dose of either the lyophilized formulation (Butantan),or the placebo. All participants included in both steps will be followed by a period of five years after their inclusion in the study. The vaccines will be administered at dose of 1000 PFU (for each of the vaccine viruses),and both vaccines and the placebo will be administered subcutaneously.