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

Launched by MAHIDOL UNIVERSITY · Apr 1, 2025

Keywords

ClinConnect Summary

The clinical trial called DHIT-Immune is investigating the safety and immune response of a dengue challenge virus in healthy individuals who have already been exposed to dengue. The study aims to understand how this controlled virus affects people who have some immunity against dengue, as most dengue cases occur in areas where people have already encountered the virus. Researchers will recruit 12 healthy participants aged 18 to 40 years from Bangkok, Thailand, who meet specific criteria, such as being of Thai nationality, having a certain level of immunity to other dengue types, and not having any serious health issues that could complicate the study.

Participants in this trial will first be exposed to a weakened form of the dengue virus and monitored for any reactions or symptoms. After the safety assessment, they will receive a complete course of dengue vaccination to help protect against future infections. Throughout the study, researchers will focus on the participants' immune responses and safety to better understand how the body reacts to dengue in those who have some prior immunity. It's important to note that participants must meet specific health and lifestyle criteria to join, and they will need to sign consent forms and adhere to study protocols.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • 1. Thai healthy volunteers, aged between 18 to 40 years old, weight is greater than or equal to 50 kg and have Thai language literacy.
• • 2. Have not given blood donation in the past 3 months.
• • 3. Education: high school diploma or above
• • 4. 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
• • 5. Willingness to participate in the study as evidenced by signing the informed consent document.
• • 6. 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:
• • 1. 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.
• • 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 receiving virus administration, or anticipated receipt of any vaccine during the 28 days following rDEN2Δ30-7169 administration.
• • 13. Has an obvious history of receiving any type of dengue vaccine or has previously participated in dengue vaccine research.
• • 14. 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.
• • 15. History of allergy to Qdenga vaccine or any components of the vaccine.
• • 16. Previous episode of severe dengue infection defined by WHO 2009
• • 17. 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).
• • 18. A participant with hemoglobin level less than 10 g/dL at initial screening.
• • 19. Body temperature is greater than or equal to 38.0 °C (Oral)
• • 20. HIV infection, as indicated by anti-HIV screening assays.
• • 21. Hepatitis C virus (HCV) infection, as indicated by anti-HCV screening assays.
• • 22. Hepatitis B virus (HBV) infection, as indicated by hepatitis B surface antigen (HBsAg) and/or anti-HBc screening.
• • 23. 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.