Post exposure prophylaxis for leprosy in the Comoros and Madagascar

Project Details


Global control of leprosy, an ancient infectious disease caused by Mycobacterium leprae (M. leprae), has stalled and needs new interventions. Post exposure prophylaxis (PEP) is one of the key interventions suggested to overcome the stalemate. Currently single dose Rifampicin (SDR) is the regimen of choice but new strategies and tools are required to target individuals at risk of developing leprosy or transmitting the bacterium. We propose to evaluate the impact of three different approaches to SDR PEP on new leprosy case detection rates in highly endemic villages on the Comoros and Madagascar, assessing the effectiveness of inclusion of different sets of contacts. We will conduct a community randomized trial in which highly endemic villages will be randomized to one of four study arms, comparing the current baseline, i.e. no PEP (arm 1), to intervention arms in which SDR PEP is provided to household contacts only (arm 2), to all contacts within a radius of 100 meters (arm 3), or to household contacts plus individuals seropositive for anti-M. leprae PGL-I antibodies living within a radius of 100 meters (arm 4). We selected highly endemic villages based on data for the period 2012-2016. In these villages we will conduct four annual door-to-door surveys. The first survey will serve as a baseline and will also be used to outline high risk zones within the villages allocated to study arms 3 and 4 by applying a 100m radius buffer around each household with an incident case in the preceding five years. PEP will then be provided in arms 2-4. Surveys will be repeated once yearly. After the second and third survey, risk zones will be redrawn based on cases reported over the preceding five-year period and PEP will be provided accordingly. The fourth and final survey will be used to calculate comulative incidence rates per study arm since baseline. Prior to starting we will conduct a qualitative study to identify optimal ways of implementation, avoiding possible obstacles related mainly to acceptability. In order to correlate patterns of clustering of leprosy at village and island level with the results observed in the four study arms, a molecular study based on genotyping of M. leprae bacteria will be performed, together with a social network analysis of close contacts.
The outcomes of this project will have important programmatic implications for leprosy control and will likely show how to turn off the tap of ongoing M. leprae transmission.
Effective start/end date1/09/1828/02/23


  • The European & Developing Countries Clinical Trials Partnership : €2,999,478.80