Causal pathways and cost-effectiveness of DREAMS' impact on psycho-social mediators, social norms, and adolescent health outcomes in rural and urban K

少女和青年妇女的艾滋病毒感染率一直高于男性同龄人，特别是在东非和南部非洲，这导致对有针对性的艾滋病毒预防进行大量投资。降低艾滋病毒发病率的障碍是多方面的，供资机构越来越多地支持提供复杂的干预措施。全面投资于青少年发展，包括预防艾滋病毒，对于实现可持续发展目标至关重要，并可为健康、教育和社会经济福祉带来短期和长期效益。了解综合干预措施的影响程度和机制，可以提供关于如何修改这些措施以提高其效力或使其适应其他情况的见解。为了提高我们的知识和优化AGYW之间的多部门艾滋病毒规划，该博士旨在通过分析肯尼亚两个环境中AGYW前瞻性队列的大型观察性定量数据集，从一个规模扩大的复杂干预（“梦想”）的独立评估中学习：内罗毕和锡亚亚（肯尼亚西部，农村）的非正式城市住区。自2016年以来，DREAMS（坚定、有韧性、有能力、无艾滋病、有指导、安全生活）伙伴关系已在10个艾滋病毒高负担非洲国家的约60个地区实施，并将在2021年继续实施。梦想不是随机的，目标是最脆弱的AGYW。DREAMS核心一揽子计划提供全面的艾滋病毒预防方案，以降低青年男女的风险，并加强对个人和环境的支持。个人一级的干预措施旨在增强青年妇女协会的能力，包括艾滋病毒检测服务、社会资产建设或性健康和生殖健康服务。背景层面的干预措施包括社会保障计划，全社区努力解决预防暴力的社会规范，以及降低AGYW男性性伴侣艾滋病毒风险的战略。2016年至2019年期间进行的独立评估的当前研究表明，随着时间的推移，多种干预措施的吸收和分层得到改善，并在两种情况下达到了AGYW的高比例。参与DREAMS对一些结果（如社会支持和接受艾滋病毒检测）有积极和一致的影响，但对其他结果（例如，最近怀孕）因环境不同而不同，年轻AGYW（15-17岁）与年长AGYW（18-22岁）之间也不同。在这一早期工作的基础上，该项目试图更详细地解释这些发现，并探索从DREAMS干预措施的因果关系途径，通过潜在的心理-社会调解人到与社会保障行为保护和生物保护有关的重要发展健康成果。通过使用因果推理方法分析观察数据，我将在新兴理论方法框架（如假设试验仿真和因果中介分析）的指导下进行研究，并应用先进的统计方法分析这些数据。这将使我能够进一步理解如何从非随机研究中获得可靠的因果效应估计，并为其他研究人员提供可以应用于他们工作的知识。通过进一步的培训促进了学生，我将提高我在社会研究方法和卫生经济学，这是回答一些研究问题以及定量统计分析的关键跨学科技能。这个博士的见解将有助于加强DREAMS的持续规划，更广泛地说，将为旨在了解如何改善和优化AGYW中艾滋病毒预防的复杂，多部门干预措施的应用研究做出宝贵贡献。

Persistently higher rates of HIV infection among adolescent girls and young women (AGYW) compared to their male peers, especially in East and Southern Africa has led to large investments in targeted HIV prevention. Barriers to reducing HIV incidence are multi-faceted, and funding agencies are increasingly supporting delivery of complex interventions. Comprehensive investments in adolescent development, including HIV prevention, are crucial in achieving the Sustainable Development Goals, and can yield short as well as long-term benefits for health, education and social-economic wellbeing. Understanding the magnitude and mechanisms of impact for comprehensive interventions can provide insights on how to modify them to improve their effectiveness, or adapt them to other contexts. To enhance our knowledge and optimise multi-sectoral HIV programming among AGYW, this PhD aims to learn from an independent evaluation of a scaled-up complex intervention ("DREAMS"), by analysing large, observational quantitative datasets from prospective cohorts of AGYW in two settings in Kenya: informal urban settlements in Nairobi and Siaya (western Kenya, rural). The DREAMS (Determined, Resilient, Empowered, AIDS-free, Mentored, Safe lives) Partnership was implemented across ~60 districts in 10 African countries with high HIV burden since 2016, and implementation is continuing during 2021. DREAMS was not randomised, and aimed to target the most vulnerable AGYW. The DREAMS core package provides comprehensive HIV prevention programs to decrease risk among AGYW and enhance supports at the individual and contextual levels. Interventions at the individual level aim to empower AGYW, and include HIV testing services, social asset building, or sexual and reproductive health services. Contextual-level interventions include social protection programs, community-wide efforts to address social norms for violence prevention, and strategies to reduce HIV risk among the male sexual partners of AGYW.Current research from the independent evaluation conducted between 2016 and 2019 shows that uptake and layering of multiple interventions improved over time and reached high proportions of AGYW in both settings. Participation in DREAMS had positive and consistent impacts on some outcomes like social support and uptake of HIV testing, but impacts on other outcomes (e.g., recent pregnancy) differed by setting, and between younger AGYW (15-17 years) vs older (18-22 years). Building on this earlier work, this project seeks to explain these findings in greater detail, and explore the causal pathways from DREAMS interventions, through potential psycho-social mediators to important developmental health outcomes relating to social protection behavioural protection, and biological protection. By analysing observational data using causal inference approaches, I will conduct my research guided by emerging theoretical methodological frameworks such as emulation of hypothetical trials, and causal mediation analysis, and apply advanced statistical methods for analysing these kinds of data. This will allow me to advance my understanding of how to obtain reliable causal estimates of effect from non-randomised studies, and contribute knowledge that other researchers can apply in their work. Through further training facilitated by the studentship, I will enhance my interdisciplinary skills in social research methods and health economics, which are crucial for answering some of the research questions alongside the quantitative statistical analysis. Insights from this PhD will help strengthen continued programming of DREAMS, and more broadly will make a valuable contribution to applied research aimed at understanding how to improve and optimise complex, multi-sectoral intervention delivery for HIV prevention among AGYW.