Phase I Study of the Safety and Immunogenicity of rDEN1delta30, a Live Attenuated Virus Vaccine Candidate for the Prevention of Dengue Serotype 1

More than 2 billion people living in tropical and subtropical regions of the world are at risk of dengue virus infection. Dengue viruses cause dengue fever, as well as the more severe dengue hemorrhagic fever/shock syndrome, and dengue virus infection is the leading cause of hospitalization and death in children in several tropical Asian countries. This study will evaluate the safety and immunogenicity of a live, attenuated dengue virus called rDEN1delta30, which is derived from the Western Pacific DEN1 serotype. This study will last 180 days. Participants in Cohort 1 will be randomly assigned to receive rDEN1delta30 or placebo at study entry. Cohort 2 will begin only after safety review of all participants in Cohort 1. Participants in Cohort 2 will receive a higher dose of rDEN1delta30 or placebo. After vaccination, participants will be asked to monitor their temperature every day for 16 days. Study visits will occur every other day after vaccination until Day 16, followed by 4 additional visits at selected days through Day 180. Blood collection and a targeted physical exam will occur at each study visit. Some participants will be asked to undergo a skin biopsy or additional blood collection at selected visits.