Safety and Immune Response to Two Doses of rDEN2/4delta30 Dengue Vaccine

Inclusion Criteria: * Good general health as determined by means of the screening procedures. * Available for the duration of the study (32 weeks for cohort 1 and 23 weeks for cohort 2) * Willing to use effective methods of contraception Exclusion Criteria: * Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, or renal disease by history, physical examination, and/or laboratory studies * Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator will affect the ability of the volunteer to understand and cooperate with the requirements of the study protocol * Neutropenia as defined by an ANC ≤1500/mm3 * ALT level above the laboratory-defined upper limit of normal * Serum creatinine level above the laboratory-defined upper limit of normal * Any other condition that, in the opinion of the investigator, would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol. * Medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months * History of a severe allergic reaction or anaphylaxis * Severe asthma (emergency room visit or hospitalization within the last 6 months) * Positive HIV-1 serology by screening and confirmatory assays * Positive for hepatitis C virus (HCV) by screening and confirmatory assays * Positive hepatitis B surface antigen (HBsAg) by enzyme-linked immunosorbent assay (ELISA) * Known immunodeficiency syndrome * Use of corticosteroids (excluding topical or nasal) or immunosuppressive drugs within 30 days of starting this study * Receipt of a live vaccine within the 4 weeks or a killed vaccine within the 2 weeks prior to entry into the study * Has had spleen surgically removed * Receipt of blood products within the 6 months prior to study entry * History or serologic evidence of previous dengue virus infection or other flavivirus infection (e.g. yellow fever virus, St. Louis encephalitis, West Nile virus). * Previous receipt of yellow fever or dengue vaccine (licensed or experimental) * Persons who have received any investigational agent in the 30 days prior to study entry * Persons who have definite plans to travel to a dengue endemic area during the study