Safety, Virological and Immunological Assessment of Live Attenuated Dengue Serotype 2 rDEN2delta30-7169.

Inclusion Criteria: 1. Thai healthy volunteers, aged between 18 to 30 years old and weight is greater than or equal to 45 kg and have Thai language literacy. 2. Don't have any history of previous dengue, zika or Japanese encephalitis virus infection 3. Have not given blood donation in the past 3 months 4. Education: higher than high school 5. Display flavivirus immunity profile defined by the standard PRNT 50% (PRNT50) as follows: flavivirus naïve is defined as the PRNT50 titer against * DENV1 \< 1:5 * DENV2 \< 1:5 * DENV3 \< 1:5 * DENV4 \< 1:5 * ZIKV \< 1:5 * JEV \< 1:5 6. Willingness to participate in the study as evidenced by signing the informed consent document. 7. Female participants of childbearing potential should be agreed to either abstinence or use at least one primary form of contraception from the time of screening for rDEN2Δ30-7169 administration until 1 month after complete course of Dengvaxia® vaccination (Study Day 568). Exclusion Criteria: 1. For female participants: Currently pregnant, as determined by positive β-human choriogonadotropin (HCG) test or breast-feeding, and given birth or abortion within 6 months. 2. History of previous acute undifferentiated febrile illness leading to hospitalization in the past 3 months 3. Behavioral, cognitive, or psychiatric disease that, in the opinion of the investigator, affects the subject's ability to understand and cooperate with the requirements of the study protocol. 4. Any significant alcohol or drug abuse in the past 12 months that has caused medical, occupational, or family problems, as indicated by subject history. 5. History of a severe allergic reaction or anaphylaxis 6. Severe asthma (emergency room visit or hospitalization within the last 6 months). 7. Any known immunodeficiency syndrome. 8. Having any pre-existing medical conditions consist of thrombocytopenia, autoimmune disease and cancer based on history, physical examination, and/or laboratory studies. 9. Current use of anticoagulant medications (this includes anti-platelet medication such as aspirin or non-steroidal anti-inflammatory medications). 10. Use of corticosteroids (excluding topical or nasal) or immunosuppressive drugs within 28 days prior to or following vaccination. An immunosuppressive dose of corticosteroids is defined as ≥ 10 mg of a prednisone equivalent per day for ≥ 14 days. 11. Asplenia 12. Receipt of any vaccine within 28 days or a killed vaccine within 14 days prior to receive virus administration, or anticipated receipt of any vaccine during the 28 days following rDEN2∆30-7169 administration. 13. Receipt of blood products within the past 6 months, including transfusions or immunoglobulin, or anticipated receipt of any blood products or immunoglobulin during the 28 days following rDEN2∆30-7169 administration. 14. Previous receipt of a flavivirus vaccine (licensed or experimental). 15. Screening laboratory values of Grade 1 or above (as defined in this protocol) for ANC (\<750 /mm3), Platelet (\<100,000 /mm3), PT (\> 1.25 x ULN), APTT (\> 1.66 x ULN), ALT (\>2.5 x ULN) and serum creatinine (\> 1.3 x ULN OR Increase to \>1.3 x participant's baseline) 16. Body temperature higher than 37.5 °C 17. HIV infection, as indicated by anti-HIV screening assays. 18. Hepatitis C virus (HCV) infection, as indicated by anti-HCV screening assays. 19. Hepatitis B virus (HBV) infection, as indicated by hepatitis B surface antigen (HBsAg) and/or anti-HBc screening. 20. Any other condition that, in the opinion of the investigator, would jeopardize the safety or rights of a subject participating in the trial, or would render the subject unable to comply with the protocol.