Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK.
School of Computing, Electronics and Mathematics, Coventry University, Coventry, UK.
Health Econ. 2021 Mar;30(3):659-679. doi: 10.1002/hec.4211. Epub 2020 Dec 29.
Pre-exposure prophylaxis (PrEP) to prevent human immunodeficiency virus (HIV) enables female sex workers (FSWs) to protect themselves from HIV without relying on clients using condoms. Yet, because PrEP reduces HIV risk, financial incentives to not use condoms may lead to risk compensation: reductions in condom use and/or increases in commercial sex, and may reduce the price of unprotected sex. In this analysis, we integrate market forces into a dynamic HIV transmission model to assess how risk compensation could change the impact of PrEP among FSWs and clients. We parameterise how sexual behavior may change with PrEP use among FSWs using stated preference data combined with economic theory. Our projections suggest the impact of PrEP is sensitive to risk compensatory behaviors driven by changes in the economics of sex work. Condom substitution could reduce the impact of PrEP on HIV incidence by 55%, while increases in the frequency of commercial sex to counter decreases in the price charged for unprotected sex among PrEP users could entirely mitigate the impact of PrEP. Accounting for competition between PrEP users and nonusers exacerbates this further. Alternative scenarios where increases in unprotected sex among PrEP users are balanced by decreases in non-PrEP users have the opposite effect, resulting in PrEP having much greater impact. Intervention studies need to determine how HIV prevention products may change the economics of sex work and provision of unprotected sex to enable a better understanding of their impact.
暴露前预防（PrEP）可防止人体免疫缺陷病毒（HIV）感染，使性工作者（FSW）无需依赖客户使用安全套即可保护自己免受 HIV 感染。然而，由于 PrEP 降低了 HIV 风险，不使用安全套的经济激励可能导致风险补偿：使用安全套的减少和/或商业性交易的增加，并且可能降低无保护性行为的价格。在这项分析中，我们将市场力量纳入动态 HIV 传播模型，以评估风险补偿如何改变 FSW 和客户中 PrEP 的影响。我们使用基于经济理论的陈述偏好数据来参数化性工作者使用 PrEP 时性行为可能如何变化。我们的预测表明，PrEP 的影响对性工作经济学变化驱动的风险补偿行为敏感。 condom 的替代可能会使 PrEP 对 HIV 发病率的影响降低 55%，而 PrEP 用户为应对未保护性行为价格下降而增加商业性交易的频率，则可能完全抵消 PrEP 的影响。考虑到 PrEP 用户和非用户之间的竞争，情况会进一步恶化。在 PrEP 用户中无保护性行为的增加与非 PrEP 用户中无保护性行为的减少相平衡的替代方案则会产生相反的效果，从而使 PrEP 的影响更大。干预研究需要确定 HIV 预防产品如何改变性工作和无保护性行为的提供的经济学，以更好地了解其影响。
