Impact assessment of single dose rifampicin post-exposure prophylaxis

Background/Introduction

Leprosy control remains a challenge in Nepal. Single-dose rifampicin post-exposure prophylaxis (SDR-PEP) shows promise in reducing leprosy incidence among contacts of index cases, contributing to reducing the transmission of Mycobacterium (M.) leprae. This study evaluates the effectiveness of routine SDR-PEP implementation in Nepal in addition to contact screening, focusing on its impact on reducing leprosy risk among contacts and potential population-level effects.
Methodology

We conducted a retrospective cohort study to compare leprosy case notification rates and leprosy risk among close contacts. We compared two districts implementing SDR-PEP (the intervention group) and two without (the comparator group). Data from 2015 onwards included demographics, index case types, and contact relationships. Statistical analyses, including Cox regression and Kaplan-Meier survival curves, assessed the impact of SDR-PEP implementation.

Findings

All four districts showed a decrease in case notification rates since 2015, with the steepest decline in the intervention districts. The risk of developing leprosy among contacts was significantly lower in the intervention districts (HR 0.28, 95% CI 0.18-0.44). SDR-PEP offered 72% protection, consistent over time, as shown in Kaplan-Meier plots. The protective effect was equally strong in blood-related contacts (HR 0.29 versus 0.27 in others, p=0.32), and the proportion of MB cases among incident cases was not significantly different post-PEP (51.4% vs. 53.6%, p=0.82).

Conclusions

This study demonstrates the substantial protective effect of integrating SDR-PEP in routine leprosy control programs with contact screening, significantly lowering leprosy risk among contacts. SDR-PEP is equally effective for blood-related contacts and does not preferentially prevent PB cases. While suggesting potential population-level impact, the study design does not allow for firm conclusions at this level. Further research is needed to fully assess SDR-PEP's effectiveness in diverse contexts and optimize its implementation. Integrating SDR-PEP within well-organized contact screening programs is effective and is expected to reduce leprosy transmission when applied as a rolling intervention.

Keywords: Routine leprosy Control, Single-dose rifampicin (SDR), Post-exposure Prophylaxis (PEP), SDR-PEP Implementation, Contact Screening,

背景/引言
麻风病的防控在尼泊尔仍然是一项挑战。单剂利福平暴露后预防（SDR-PEP）在降低麻风病发病率方面展现出前景，尤其是在接触麻风病患者的群体中，有助于减少麻风分枝杆菌（M. leprae）的传播。本研究旨在评估尼泊尔常规SDR-PEP实施的效果，并在此基础上进行接触筛查，重点关注其对降低接触者麻风病风险及潜在的人口水平影响。
研究方法
我们进行了一项回顾性队列研究，以比较麻风病病例报告率和接触者中的麻风病风险。我们将实施SDR-PEP的两个区（干预组）与未实施的两个区（对照组）进行了比较。2015年及以后的数据包括人口统计学、病例类型和接触关系。通过Cox回归和Kaplan-Meier生存曲线等统计方法评估了SDR-PEP实施的影响。
研究结果
自2015年以来，所有四个区均显示出病例报告率的下降，其中干预区的下降幅度最为显著。干预区接触者发生麻风病的风险显著降低（HR 0.28，95% CI 0.18-0.44）。SDR-PEP提供了72%的保护效果，这一效果随着时间的推移保持一致，如Kaplan-Meier图所示。保护效果在血缘关系接触者（HR 0.29与其他人相比为0.27，p=0.32）中同样强劲，而在PEP后新发病例中MB病例的比例没有显著差异（51.4% vs. 53.6%，p=0.82）。
结论
本研究证实，将SDR-PEP整合到常规麻风病控制程序和接触筛查中，对降低接触者麻风病风险具有显著的防护作用。SDR-PEP对血缘关系接触者同样有效，且不会优先预防PB病例。虽然本研究提出了潜在的人口水平影响，但由于研究设计限制，尚不能在此层面得出明确结论。需要进一步的研究以全面评估SDR-PEP在不同环境中的有效性并优化其实施策略。将SDR-PEP整合到组织良好的接触筛查程序中是有效的，并有望作为滚动干预措施降低麻风病的传播。
关键词：常规麻风病控制，单剂利福平（SDR），暴露后预防（PEP），SDR-PEP实施，接触筛查