When used appropriately, pre-exposure prophylaxis (PrEP) substantially reduces the risk of HIV acquisition. Early implementation outcomes often suggest poor PrEP adherence and persistence; however, this intervention is time-limited and the need for PrEP fluctuates as risk behaviours change. In this Viewpoint we examine the current guidelines and early programmatic outcomes after starting, stopping, and restarting PrEP, and we review the implications of PrEP in relation to HIV testing algorithms. Guidelines suggest to discontinue PrEP when a person is no longer at risk for HIV, but effectively implementing this strategy requires support tools to make the decision of stopping and restarting PrEP that considers the complex relationship between risk perceptions and risk behaviours. Safely discontinuing PrEP also requires greater understanding of the daily dosing duration that is needed to protect the person after their last HIV exposure. Additionally, clear strategies are needed to re-engage a person as their HIV exposure risk changes over time.

如果使用得当，暴露前预防 (PrEP) 会大大降低感染 HIV 的风险。早期实施结果通常表明 PrEP 依从性和持久性较差；然而，这种干预是有时间限制的，对 PrEP 的需求会随着风险行为的变化而波动。在这个观点中，我们检查了当前的指南和在开始、停止和重新启动 PrEP 后的早期计划结果，并回顾了 PrEP 对 HIV 检测算法的影响。指南建议当一个人不再有感染 HIV 的风险时停止 PrEP，但有效实施该策略需要支持工具来决定停止和重新启动 PrEP，考虑风险认知和风险行为之间的复杂关系。安全停止 PrEP 还需要更深入地了解在最后一次暴露于 HIV 后保护患者所需的每日给药持续时间。此外，需要明确的策略来重新吸引一个人，因为他们的 HIV 暴露风险会随着时间的推移而发生变化。