Primary Outcome Measures:
- Safety, as defined by frequency of vaccine-related adverse events, as classified by both intensity and severity through active and passive surveillance [ Time Frame: Throughout study ] [ Designated as safety issue: Yes ]
- Immunogenicity, as determined by anti-DEN3 neutralizing antibody measured on Days 0, 21, 28, 42, and 180 [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- Assess the frequency, quantity, and duration of viremia in each dose cohort studied [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Determine the number of vaccinees infected with rDEN3/4delta30(ME) [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Determine cellular targets of vaccine infection, including peripheral blood mononuclear cells (PBMCs) and skin from participants who are willing to undergo skin biopsy [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
- Compare the infectivity rates, safety, and immunogenicity between dose groups [ Time Frame: At study completion ] [ Designated as safety issue: No ]
- Evaluate the immunopathological mechanism of vaccine-associated rash in those volunteers who are willing to undergo skin biopsy [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
Dengue viruses, which cause dengue fever and dengue shock syndrome, are a major cause of morbidity and mortality in several of the world's tropical and subtropical regions. The rDEN3/4delta30(ME) vaccine is a live attenuated dengue virus vaccine that may be protective against dengue virus serotype 3 (DEN3). The purpose of this study is to evaluate the safety and immunogenicity of the rDEN3/4delta30(ME) vaccine in healthy adults.
This study will last 40 weeks. Participants will be randomly assigned to receive one of three doses of rDEN3/4delta30(ME) or placebo. Participants in Group 1 will receive the middle dose of rDEN3/4delta30(ME) or placebo at study entry. Group 2a will begin enrollment after the immunogenicity review of all participants in Group 1. Participants in Group 2a will receive the highest dose of rDEN4delta30(ME) or placebo at study entry. Group 2b will begin enrollment after the immunogenicity review of all participants in Group 2a. Participants in Group 2b will receive the lowest dose of rDEN4delta30(ME) or placebo.
After vaccination, participants in all groups will be followed closely every other day for the first 16 days of the study. Participants will take their temperature three times a day through Day 16 and record each measurement in a diary. After Day 16, participants will have study visits on Days 21, 28, 42, and 180; a physical exam and blood collection will occur at all visits. Some participants may be asked to join a skin biopsy substudy.