How should you implement PEP in your country?

A special Leprosy Research Initiative focus.

How should you implement PEP in your country?

In recent years, much talk in the leprosy sector has been centred on post-exposure prophylaxis (PEP). Through administering a single dose of the antibiotic rifampicin (SDR-PEP) to contacts of new leprosy cases, we can reduce the chances that they will develop leprosy by up to 60 percent. There are also trials underway to help us perfect a PEP regimen that would bring that number closer to 100 percent.

However, because the dawn of PEP for leprosy is in the recent past, although we have a standard approach to PEP (targeting 20 close contacts per index patient), we have not yet understood the best approaches for different circumstances, particularly in terms of endemicity, infrastructure, and health system capacity. That has been the goal of the PEP4LEP trial.

Comparing skin camp interventions with health centre interventions

Funded by the Leprosy Research Initiative and the European & Developing Countries Clinical Trials Partnership (EDCTP2, which is co-funded by the European Union), this project has been working in communities across Mozambique, Ethiopia, and Tanzania comparing the effectiveness and feasibility of a skin camp to a health centre-based leprosy prophylaxis intervention. They have been comparing the rate of leprosy patients detected and the delay in case detection; and comparing the acceptability and cost-effectiveness of the two interventions..

The team began by training government healthcare workers in leprosy case detection and detection of other skin diseases using NLR’s Skin App. After this, they began the cluster-randomised implementation trial of the skin camp approach and the health centre approach.

In the skin camp approach, government healthcare workers have been visiting communities to host skin camps. The invitations to these skin camps have been exclusively for people living in the 20 houses closest to the index case. In this process, the people attending the skin camps are not told which neighbour was diagnosed with leprosy in their neighbourhood so that this individual will not face any stigma or discrimination. At the skin camps, attendees will be screened for a variety of skin diseases and if they are eligible, they will receive SDR-PEP.

In the health centre approach, members of the household of an index patient will be requested to visit the nearest healthcare centre by the index patient, where they will be screened for leprosy and other skin diseases, and offered SDR-PEP if they are eligible.

The researchers have been working to understand which approach is most effective, the cost-effectiveness of each approach, and whether these approaches are acceptable to index patients, to their close contacts and to health staff and policy makers. They want their findings to inform conversations with governments so that policymakers will be better informed about the possibility of implementing PEP. Because of delays related to COVID-19, a follow-up project called PEP4LEP 2.0 (funded by the Global Health EDCTP3 Joint Undertaking, co-funded by the European Union) commenced in April last year and will be running until early 2026.

The findings have so far been very positive

By the end of the PEP4LEP 2.0 project, the team had a target of screening 33,000 people through more than 300 skin camps and 3,000 people through the health centre approach.

Do these active case finding methods work?

At the moment, the findings are preliminary, with full findings expected when data collection and analysis is finished in mid-2026. However, they have found that roughly 1 percent of skin camp participants and 2 percent of health centre participants had symptoms of leprosy. These active case finding approaches are leading to more cases of leprosy being detected.

Beyond this, they found that around 50 percent of skin camp participants had some other form of skin disease, such as scabies or fungal infections. The team believe this is a consequence of limited health care access, health education, WASH facilities, and the warm and humid climate in these settings. Through the skin camps, all of these individuals with skin conditions were able to receive treatment or referrals for treatment.

Roughly 1 percent of skin camp participants and 2 percent of health centre participants had symptoms of leprosy

Are these methods acceptable to those involved?

The team have found that both of these processes pass the acceptability test. Their qualitative assessments with trial participants demonstrated that they were very happy to receive preventative medication and to have this kind of integrated skin screening. From a quantitative perspective, they found that over 99 percent of eligible close contacts were happy to receive SDR-PEP.

Do these approaches allow for the interruption of transmission?

From an epidemiological perspective, the team have found that their metrics have been more complex and will require longer-term surveillance. They understood from the outset that case detection rates would go up over the first years of the project as active case detection began. By the third year they expected this to level out to pre-active case finding rates before starting to decrease beyond that level in the subsequent years. This is an indicator that will only become clear in the years to come.

With this in mind, the team had hoped to rely on the case detection delay rate as a meaningful indicator, with this number expected to drop over the first years of implementation. However, they found that the shortcomings of previous case detection efforts in these countries was leading to a backlog that meant very high case detection delay rates.

This has proved to be unfortunate, but an interesting finding nonetheless. It demonstrates that patients who had been living with undiagnosed and untreated leprosy - sometimes for several years - were finally identified and diagnosed through the project. Following diagnosis, they were able to start treatment, effectively halting disease progression and stopping further transmission. By also screening and offering leprosy prevention to their contacts, the project hopes to make an impact on transmission of the leprosy bacteria in these settings. It will be data in the years to come that reveal whether this approach is effective, both in terms of new cases and the case detection delay.

Are these approaches cost-effective?

It is undoubtedly true that the skin camp approach is time-intensive and cost-intensive, but these community events also diagnose many skin diseases, likely resulting in a greater over-all health impact. The team are working with Erasmus University from Rotterdam, the Netherlands, to understand what the cost saving of this approach will be in the long run. They want to know how many cases of leprosy will be prevented and what the cost saving would be from that in terms of supporting patients through treatment and reduced cost of providing PEP. They would also demonstrate the number of leprosy-related disability cases that might be prevented, although data on the financial impact of that would be harder to demonstrate.

This cost-effectiveness question would eventually be translated into compelling advocacy messages. The team expect that they will be able to say skin camps are an investment that will lead to great cost-savings within 10 years. The integrated skin disease approach used is also supported by the World Health Organization, and reflected in the resolution “Skin diseases as a global public health priority” from the World Health Assembly which was adopted in May 2025. Governments are always keen to understand the impact of interventions that they are considering and the modelling from this study could be the key to encouraging take-up of PEP by governments.

Could the findings from this project be replicated elsewhere?

The team acknowledge that different contexts require different approaches. In very high-endemic communities, a blanket approach to case finding and PEP may be better suited. Equally, we have not quite cracked the best method for PEP implementation in urban settings.

However, the team expect that the approach taken in this study could prove very effective in settings with mid-to-high level endemicity and in rural or semi-rural areas. They also believe that the methods they have considered would be just as easy to replicate with an enhanced PEP regimen.

Because the approach integrates other skin diseases, it is an easier sell to governments, particularly following the recent World Health Assembly resolution on skin diseases, which has made this a priority for governments.

As more data pours in on transmission rates and case detection delays, the PEP4LEP and PEP4LEP 2.0 projects could provide leprosy teams worldwide with the data they need to implement PEP effectively. For more information on the projects and funders, visit the project page.

Do you feel confident about how to implement PEP in your context?

Yes, we have tested and perfected the process
We have some ideas, but there is a lot we don't know
We have a plan but have not started implementing
We have no idea what would work best