Primary Outcome Measures:
- Occurrence of any, and grade 3 solicited adverse events (AEs) within 21 days follow-up after dose 1 of study vaccine and N antibody (GMT) to dengue vaccine serotypes 1, 2, 3 and 4, 30 days after the last study vaccine dose.
Secondary Outcome Measures:
- "Safety endpoints
- Occurrence of any, and grade 3 solicited adverse events (AEs) within 21 days follow-up after dose 2 of study vaccine;
- Occurrence of each type of any and grade 3 solicited AE within the 21-day solicited follow-up period after each dose;
- Occurrence of unsolicited AEs within 31 days (days 0-30) after any study vaccine dose;
- Occurrence of serious adverse events (SAEs) throughout the entire study period;
- Occurrence of alert values for safety laboratory determinations within 31 days after each vaccine dose.
- Immunogenicity endpoints
- N antibody ≥ 1:10 to each dengue vaccine serotype, 30 days after each dose;
- Tetravalent N antibody, 30 days after each dose;
- Occurrence of measurable dengue viremia at specified time points following each vaccine dose.
- Additional endpoints
- Selected cell-mediated immunity readouts after each dose
- Occurrence of disseminated infections among blood fed mosquitoes after dose 1
Subjects will be randomized into one of 6 groups. One group will receive a placebo vaccine and the others will receive one of 5 different dengue vaccine formations. Each subject will receive two doses six months apart. Study subjects who elect to participate in a mosquito transmissibility component of the study will undergo mosquito feedings during each of the two assigned follow-up visits after vaccine dose 1. All subjects will have 11 venipunctures during 11 visits (i.e., screening plus 10 study visits) over a period of nine months.