Safety, Virological and Immunological Assessment of the Controlled Dengue Human Infection Model in Dengue-Immune Participants in Thailand (DHIT-Immune)

Inclusion criteria

• Thai healthy volunteers, aged between 18 to 40 years old, weight is greater than or equal to 50 kg and have Thai language literacy.
• Have not given blood donation in the past 3 months.
• Education: high school diploma or above
• Positive dengue-immune status against DENV-1 and/or DENV-3 and/or DENV-4 with naive DENV-2 status by the standard FRNT 50% (FRNT50) as follows: FRNT50 titer against

• DENV1 ≥ 1:5 and/or
• DENV3 ≥ 1:5 and/or
• DENV4 ≥ 1:5 with
• DENV2 ≤ 1:16
• Willingness to participate in the study as evidenced by signing the informed consent document.
• 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 Dengue vaccination (Study Day 298).

Exclusion criteria

• For female participants: Currently pregnant, as determined by positive urine human choriogonadotropin (HCG) test or breast-feeding, and given birth or abortion within 6 months.
• History of previous acute undifferentiated febrile illness leading to hospitalization in the past 3 months.
• 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.
• Any significant alcohol or drug abuse in the past 12 months that has caused medical, occupational, or family problems, as indicated by subject history.
• History of a severe allergic reaction or anaphylaxis.
• Severe asthma (emergency room visit or hospitalization within the last 6 months).
• Any known immunodeficiency syndrome.
• Having any pre-existing medical conditions consist of thrombocytopenia, autoimmune disease and cancer based on history, physical examination, and/or laboratory studies.
• Current use of anticoagulant medications (this includes anti-platelet medication such as aspirin or non-steroidal anti-inflammatory medications).
• 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.
• Asplenia
• Receipt of any vaccine within 28 days or a killed vaccine within 14 days prior to receiving virus administration, or anticipated receipt of any vaccine during the 28 days following rDEN2Δ30-7169 administration.
• Has an obvious history of receiving any type of dengue vaccine or has previously participated in dengue vaccine research.
• 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 rDEN2Δ30-7169 administration.
• History of allergy to Qdenga vaccine or any components of the vaccine.
• Previous episode of severe dengue infection defined by WHO 2009
• 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 plasma creatinine (> 1.3 x ULN OR Increase to >1.3 x participant's baseline).
• A participant with hemoglobin level less than 10 g/dL at initial screening.
• Body temperature is greater than or equal to 38.0 °C (Oral)
• HIV infection, as indicated by anti-HIV screening assays.
• Hepatitis C virus (HCV) infection, as indicated by anti-HCV screening assays.
• Hepatitis B virus (HBV) infection, as indicated by hepatitis B surface antigen (HBsAg) and/or anti-HBc screening.
• 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.