Population Health Sciences, University of Bristol, Bristol, UK.
Wits RHI, University of the Witwatersrand, Johannesburg, South Africa.
J Int AIDS Soc. 2023 Feb;26(2):e26063. doi: 10.1002/jia2.26063.
In 2016, South Africa (SA) initiated a national programme to scale-up pre-exposure prophylaxis (PrEP) among female sex workers (FSWs), with ∼20,000 PrEP initiations among FSWs (∼14% of FSW) by 2020. We evaluated the impact and cost-effectiveness of this programme, including future scale-up scenarios and the potential detrimental impact of the COVID-19 pandemic.
A compartmental HIV transmission model for SA was adapted to include PrEP. Using estimates on self-reported PrEP adherence from a national study of FSW (67.7%) and the Treatment and Prevention for FSWs (TAPS) PrEP demonstration study in SA (80.8%), we down-adjusted TAPS estimates for the proportion of FSWs with detectable drug levels (adjusted range: 38.0-70.4%). The model stratified FSW by low (undetectable drug; 0% efficacy) and high adherence (detectable drug; 79.9%; 95% CI: 67.2-87.6% efficacy). FSWs can transition between adherence levels, with lower loss-to-follow-up among highly adherent FSWs (aHR: 0.58; 95% CI: 0.40-0.85; TAPS data). The model was calibrated to monthly data on the national scale-up of PrEP among FSWs over 2016-2020, including reductions in PrEP initiations during 2020. The model projected the impact of the current programme (2016-2020) and the future impact (2021-2040) at current coverage or if initiation and/or retention are doubled. Using published cost data, we assessed the cost-effectiveness (healthcare provider perspective; 3% discount rate; time horizon 2016-2040) of the current PrEP provision.
Calibrated to national data, model projections suggest that 2.1% of HIV-negative FSWs were currently on PrEP in 2020, with PrEP preventing 0.45% (95% credibility interval, 0.35-0.57%) of HIV infections among FSWs over 2016-2020 or 605 (444-840) infections overall. Reductions in PrEP initiations in 2020 possibly reduced infections averted by 18.57% (13.99-23.29). PrEP is cost-saving, with $1.42 (1.03-1.99) of ART costs saved per dollar spent on PrEP. Going forward, existing coverage of PrEP will avert 5,635 (3,572-9,036) infections by 2040. However, if PrEP initiation and retention doubles, then PrEP coverage increases to 9.9% (8.7-11.6%) and impact increases 4.3 times with 24,114 (15,308-38,107) infections averted by 2040.
Our findings advocate for the expansion of PrEP to FSWs throughout SA to maximize its impact. This should include strategies to optimize retention and should target women in contact with FSW services.
2016 年，南非（SA）启动了一项扩大女性性工作者（FSW）人群中暴露前预防（PrEP）的国家方案，到 2020 年，FSW 中约有 20,000 人开始使用 PrEP（约占 FSW 的 14%）。我们评估了该方案的影响和成本效益，包括未来的扩大规模方案以及 COVID-19 大流行的潜在不利影响。
我们对南非的 HIV 传播模型进行了调整，纳入了 PrEP。利用全国 FSW 研究（67.7%）和南非 TAPS PrEP 示范研究（80.8%）中报告的自我报告 PrEP 依从性估计值，我们根据检测到药物水平的 FSW 比例（调整范围：38.0-70.4%）对 TAPS 估计值进行了下调。该模型对低（检测不到药物；0%疗效）和高（检测到药物；79.9%；95%CI：67.2-87.6%疗效）依从性的 FSW 进行分层。FSW 可以在依从性水平之间转换，高依从性 FSW 的失访率较低（aHR：0.58；95%CI：0.40-0.85；TAPS 数据）。该模型经过校准，可以每月提供全国范围内 FSW 中 PrEP 的扩大规模数据，包括 2020 年 PrEP 启动的减少。该模型预测了当前方案（2016-2020 年）和未来方案（2021-2040 年）的影响，当前覆盖率或启动和/或保留率翻倍。使用已发表的成本数据，我们评估了当前 PrEP 提供的成本效益（医疗保健提供者视角；3%贴现率；时间范围 2016-2040 年）。
根据国家数据进行校准，模型预测显示，2020 年目前有 2.1%的 HIV 阴性 FSW 在使用 PrEP，2016-2020 年期间，PrEP 预防了 FSW 中 0.45%（95%可信度区间，0.35-0.57%）的 HIV 感染，或总共预防了 605（444-840）例感染。2020 年 PrEP 启动减少可能使避免的感染减少了 18.57%（13.99-23.29%）。PrEP 具有成本效益，每花费 1 美元用于 PrEP，就可以节省 1.42 美元（1.03-1.99）的 ART 成本。展望未来，现有的 PrEP 覆盖率将在 2040 年前避免 5635（3572-9036）例感染。但是，如果 PrEP 启动和保留率增加一倍，那么 PrEP 覆盖率将增加到 9.9%（8.7-11.6%），到 2040 年，影响将增加 4.3 倍，将预防 24,114（15,308-38,107）例感染。
我们的研究结果主张在整个南非扩大 FSW 中 PrEP 的使用，以最大限度地提高其影响。这应包括优化保留率的策略，并应针对与 FSW 服务有接触的妇女。
