rDEN2Δ30-7169 is a dengue challenge strain that previously reports its viremia induction effect in participants with minimal symptoms in US flavivirus naïve participants. Moreover, preliminary result of five Thai dengue naïve participants from previous project (registered number NCT05476757) demonstrated 100% viremia status without severe adverse event after 60 days post-virus challenge. However, result from previous project may not fully represent the clinical manifestation and immunological responses of major population of endemic areas, where most people in endemic area have dengue immune status. Therefore, this controlled human infection model protocol proposes to challenge the attenuated virus in 12 dengue-immune participants recruited from Bangkok metropolitan area, Thailand. We aim to assess the safety, viremia, NS1 antigenemia profile, and immunogenicity of the challenge virus in the dengue immune participants. After finish safety assessment, all participants will be vaccinated with a full course of dengue vaccines to prevent recurrent dengue infection. Immunological responses after vaccination will be also evaluated the vaccine efficacy.
Our expected outcomes are all participants present viremia profiles after virus challenge without serious adverse events (SAE). The exploratory profiles include assesment of immune profiles and parameters comparison with the other dengue challenge study.
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
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.
Mahidol University
Lead sponsor
National Institutes of Health (NIH)
Collaborator
Johns Hopkins University
Collaborator