Safety and Immunogenicity of Various Formulations of Live Attenuated Tetravalent Dengue Vaccine in Healthy US Adults

Inclusion Criteria: * A healthy male or female adult 18-45 years at the time of vaccination; * Free of obvious health problems as established by medical history and physical examination before entering into the study; * Written informed consent obtained from the subject; * Able to read the Subject Information Sheet and Consent Form; * Subjects who the investigator believes can and will comply with the requirements of the protocol (e.g., completion of the diary cards, return for follow-up visits) should be enrolled in the study; * If the subject is female, she must be of non-childbearing potential, i.e. either surgically sterilized or one year post-menopausal; or, if of childbearing potential, she must be abstinent or have used adequate contraceptive precautions (i.e. intrauterine contraceptive device; oral contraceptives or other equivalent hormonal contraception, e.g. progestin implantable, cutaneous hormonal patch or injectable contraceptives) for 30 days prior to vaccination, have a negative pregnancy test within 48 hours prior to vaccination and must agree to continue such precautions for 60 days after completion of the vaccination series. Exclusion Criteria: * Pregnant or lactating female; * Female planning to become pregnant or planning to discontinue abstinence or contraceptive precautions; * History of any neurological or behavioral disorder or seizures, with the exception of a single febrile seizure in childhood; * History of drug abuse or alcohol consumption (more than 2 drinks per day); * History of allergic disease/reaction likely to be exacerbated by any component of the vaccine; * History of urticaria related to mosquito bites requiring medical attention; * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic, renal, hematologic or endocrine functional defect, as determined by physical examination or laboratory tests; * Any confirmed or suspected immunosuppressive or immunodeficient condition; * Subject seropositive for HBsAg, anti-HCV or anti-HIV; * Acute disease at the time of enrollment (acute disease is defined as the presence of a moderate or severe illness with or without fever); * (Vaccine can be administered to persons with a minor illness such as diarrhea, mild upper respiratory infection with or without low-grade febrile illness, i.e., oral temperature \<37.5°C/\<99.5°F.) * Chronic hepatomegaly, right upper quadrant abdominal pain or tenderness; * Chronic splenomegaly, left upper quadrant abdominal pain or tenderness; * Use of any investigational or non-registered drug or vaccine other than the study vaccine within 30 days preceding the study vaccine (includes placebo) or planned use during the study period; * Planned administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before each dose of the study vaccine and ending 30 days after; * A planned move to a location that will prohibit participating in the trial for 9 months after the initial vaccination; * Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within 90 days preceding the first dose or planned administration during the study period. For corticosteroids, this will mean prednisone, or equivalent, 0.5 mg/kg/day. Inhaled and topical steroids are allowed; * Administration of immunoglobulins and/or blood products within 90 days preceding the first dose or planned administration during the study period; * Any chronic systemic drug therapy to be continued during the study period (except for vitamin/mineral supplements, a single anti-hypertension medication or routine treatment for gastro-esophageal reflux).