Viremia

Persons with chronic hepatitis B (HBV) infection and active viremia are infectious and may transmit virus to others through blood/body fluid exposure. Immune tolerant treatment naive persons with hepatitis B infection express anxiety regarding disclosure of their infection status and significant fear of transmission to their partners leading to social isolation and impact on their personal lives. This study will provide data correlating serum and body fluid viral levels in persons with chronic hepatitis B infection not on therapy and those with viral suppression on long-term anti-retroviral therapy (ART) that may support the concept of "Undetectable=Untransmissible" (U=U) in patients with chronic hepatitis B.

Mentor Mothers (MMs) are peer supporters who help pregnant and postpartum women living with HIV (WLHIV) as they receive prevention of mother-to-child transmission of HIV (PMTCT) services in resource-limited settings like Kenya. Differentiated service delivery (DSD) is a care model that tailors services based on clients' needs, helping to improve both the quality and efficiency of care. This hybrid implementation-effectiveness study will test whether an enhanced MM strategy that uses DSD can be successfully carried out and improve health outcomes for mothers and infants. The study will take place at Burnt Forest Sub-District Hospital (BFSDH) in Kenya. Researchers will ask: * Can the enhanced MM strategy be delivered as planned and accepted by patients and staff? * Does the strategy improve clinical outcomes like keeping mothers in PMTCT care, achieving HIV viral suppression, completing infant HIV testing, and preventing HIV transmission to infants? Researchers will compare health outcomes before and after the strategy is introduced at BFSDH, and also compare outcomes at other similar clinics that continue with standard MM services. Women who choose to participate will meet with a MM during their routine antenatal and postnatal clinic visits. They will be offered the enhanced MM support, but can choose to receive standard care if they prefer.

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.