The role of chemoprophylaxis in reducing Hansen’s disease transmission
by Taís Loureiro Zambon,
and Marcos Cesar Florian.
The global incidence of Hansen’s disease has declined over past decades, but there are still thousands of undiagnosed cases in endemic countries and an underestimation of the true numbers of cases (1). Moreover, because it is a chronic disease, there is the possibility of late diagnosis, contributing to the occurrence of physical disabilities and continued transmission (2).
Epidemiological studies have shown that the chance of finding people with undiagnosed Hansen’s disease is about ten times higher in contacts living in the same household as people already diagnosed than in the general population (3). Therefore, contacts should be one of the main foci of plans for disease control.
In this context, chemoprophylaxis (prevention using drugs) emerges as a strategy to contain the transmission of Hansen’s disease. The basic intervention currently discussed as chemoprophylaxis is "post-exposure prophylaxis" (PEP), usually given to contacts of persons affected by Hansen’s disease, such as relatives and neighbours (4).
One of the main drugs used, particularly in clinical trials in endemic countries, is single-dose rifampicin (SDR), which has a proven effect in reducing infection in the first two years after administration (5). Rifampicin is currently the drug of choice for chemoprophylaxis because of its low cost and lower risk of adverse effects and resistance.
In Brazil, it was proposed that PEP could be implemented in Family Health Programs (Programas da Saúde da Família, PSF) allowing easy access to the person affected by Hansen’s disease and facilitating the role of health workers in the treatment and control of the disease (5). This leads to greater adherence to PEP because in most cases patients live far from the places where the medication is distributed and treatment is carried out.
However, there are still caveats to be considered. There are varied study results depending on the design of study and time of observation. In addition, the effectiveness of chemoprophylaxis is reduced in people at higher risk of illness: contacts of people with multibacillary Hansen’s disease, people living in the same household, and contacts who are genetically-related to the case (5). Finally, PEP does not alter the social determinants of Hansen’s disease.
The World Health Organization (WHO) recommends interventions for the prevention of infection and disease, but makes no recommendation about chemoprophylaxis as an intervention for Hansen’s disease because evidence for its effectiveness is limited (6).
The PEP++ program funded by Netherlands Hanseníase Relief (NHR) Brazil is a multi-centre study in the municipalities of Fortaleza and Sobral. The aim of the program is to stop the transmission of Hansen’s disease. In addition to chemoprophylaxis, the program seeks to strengthen the public health system and focus on endemic communities by improving disease control skills and promoting health education actions that disseminate knowledge and reduce stigma.
PEP++ is based on a reinforced prevention scheme. People affected by Hansen’s disease will receive three doses of a combination of rifampicin and clarithromycin. This dose is expected to be 80-90% effective, compared with 60% in the current (SR) prevention scheme. PEP++ has an innovative approach based on: i) strategies for early case detection, including the development of educational materials to improve perception and knowledge of the disease and reduce stigma; ii) capacity-building to improve health workers’ technical knowledge of diagnosis; iii) identification of Hansen’s disease clusters through geographical information system (GIS) based mapping of current and recent cases; iv) preventive chemoprophylaxis coverage in all areas of high Hansen’s disease endemicity (7).
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