The Coronavirus Disease 2019 (COVID-19) pandemic is advancing globally, and pharmaceutical prophylaxis is one solution. Here, we propose repositioning chloroquine (CQ) as prophylaxis against COVID-19. CQ blocks viral attachment and entry to host cells and demonstrates efficacy against a variety of viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. Furthermore, CQ is safe, inexpensive, and available. Here, we review the antiviral mechanisms of CQ, its in vitro activity against coronaviruses, its pharmacokinetics (PK) and adverse effects, and why it could be more efficacious as a prophylactic rather than as a therapeutic, given the infection dynamics of SARS-CoV-2. We propose two prophylactic regimens based on efficacy and risk considerations. Although it is largely preclinical data that suggest the potential of CQ, properly planned prophylactic trials and further research are urgently needed.

2019 年冠状病毒病 (COVID-19) 正在全球蔓延，药物预防是一种解决方案。在这里，我们建议重新定位氯喹 (CQ) 作为 COVID-19 的预防药物。 CQ 可阻止病毒附着和进入宿主细胞，并显示出对多种病毒的功效，包括严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2)（COVID-19 的病原体）。此外，CQ 安全、廉价且可用。在这里，我们回顾了 CQ 的抗病毒机制、其针对冠状病毒的体外活性、其药代动力学 (PK) 和不良反应，以及考虑到 SARS-CoV 的感染动态，为什么它作为预防剂而不是治疗剂可能更有效-2。我们根据疗效和风险考虑提出两种预防方案。尽管主要是临床前数据表明了 CQ 的潜力，但迫切需要适当计划的预防性试验和进一步的研究。