The Epidemiological Impact of Community-Based Skin Camps on Leprosy Control in East Hararghe Zone, Ethiopia: a Modelling Study.

Background: Leprosy is a chronic infectious disease that remains a public health challenge in many low- and middle-income countries. The mainstay of leprosy control has been early detection and treatment through active case finding. In this study, we aimed to predict the epidemiological impact of community-based skin camps to shorten the period of leprosy case detection delay in a population.

Methods: We used the individual-based model SIMCOLEP to predict the epidemiological impact of two successive community-based skin camps with 50%, 70% and 90% target population coverage conducted five years apart (in 2024 and 2029). The model was calibrated to the leprosy situation in East Hararghe zone, Ethiopia (2008-2023).

Results: There was a short-term rise in the new case detection rate due to a backlog of cases being discovered, but no difference in the long run compared to the baseline situation (i.e., no intervention). However, all strategies substantially decreased the prevalence of undiagnosed symptomatic cases in the population. Skin camps with 50% coverage resulted in 21.8% (95% CI: 20.1-23.5%) fewer cases per million in 2035, while increasing the coverage to 90% led to a reduction of 33.0% (95% CI: 31.5-34.4%) in 2035. This impact was sustained for the skin camps with 90% coverage, with a 30.9% reduction compared to baseline in 2040.

Conclusion: Our findings suggest that shortening the period of leprosy case detection delay through community-based skin camps could substantially reduce the prevalence of symptomatic cases in high endemic regions, leading to improved disease control.