Estudio sobre la transmisión y un ensayo quimioprofiláctico en contactos de pacientes de lepra: resultados de Colep / No disponible

En este trabajo se describe el modelo metodológico y hallazgos del estudio COLEP. Los objetivos del estudio son determinar la efectividad de la quimioprofilaxis con una dosis única de rifampicina e la prevención de la lepra entre contactos de pacientes de lepra y hallar características de los grupos de contacto en mayor riesgo de desarrollar lepra clínica. Estas características deben resultar útiles para los programas de control de lepra. El COLEP es un ensayo agrupado y aleatorio, a dobe ciego y controlado por placebo para determinar factores de riesgo que caracterizan los subgrupos en mayor riesgo entre el grupo contacto total de un paciente y un estudio de cohortes utilizando un grupo de referencia de entre la población general para determinar la prevalencia e incidencia de la lepra en la zona de la población estudiada. El período de seguimiento fue de 4 años. Se desarrolló un sistema de codificación explicando la distancia física y genética del contacto al paciente. Este estudio de Bangladesh incluye 1037 pacientes recién diagnosticados y sin tratamiento previo y sus 21,867 contactos. La prevalencia de la lepra entre los contactos era de 7-3 por 1000. Un total de 21,708 contactos sin rasgos ni síntomas de lepra clínica se incluyeron en un ensayo quimioprofiláctico con una dosis única de rifampicina y aleatorio a nivel del grupo de contacto en cuanto tratamiento y placebo. Los resultados de este ensayo estarán disponibles en algunos años

In this article, we describe the design, methodology and recruitment findings of the COLEP study. The objectives of this study were to determine the effective-ness of chemoprophylaxis with a single dose of rifampicin in the prevention of leprosy among contacts of leprosy patients, and to find characteristics of contact groups most at risk to develop clinical leprosy. These characteristics should be usable by routine leprosy control programmes. COLEP consists of a cluster randomized, double-blind and placebo-controlled trial, a cohort study to determine risk factors characterizing the sub-groups most at risk within the total contact group of a patient, and a cohort study using a reference group from the general population to determine the prevalence and incidence of leprosy in the total population of the study area. The follow-up period will be 4 years. A coding system was developed describing the physical and genetic distance of the contact person to the patient. This study in Bangladesh includes 1.037 newly diagnosed and previously untreated leprosy patients and their 21.867 contacts. The prevalence of leprosy among contacts was 7.3 per 1.000. a total of 21.708 contacts without sings and symptoms of clinical leprosy are included in a trial of chemoprophylaxis with single dose rifampicin, and randomized at contact group level in treatment and placebo arms. The results of this large field trial will become available in the years to come

Risk factors for the development of clinical leprosy among contacts, and their relevance for targeted interventions.

Existing knowledge on risk factors for the development of clinical leprosy among contacts of known leprosy patients is reviewed with the aim to identify factors associated with leprosy among contacts that have potential for developing effective targeted interventions in leprosy control. Different definitions of 'contact' have been used and most studies on this subject were among so-called household members. Yet several studies indicate that contacts found in other places than the household are also at risk of developing leprosy. The type of leprosy and the bacterial index are the main patient-related factors involved in transmission, but also contacts of PB patients have a higher risk of contracting leprosy as compared to the general population. The most important contact-related factors are the closeness and intensity of the contact and inherited susceptibility, while the role of age and sex of the contacts is not clear. The role of socio-economic factors is also vague. The significance of immunological and molecular markers in relation to risk of transmitting or developing leprosy is not yet fully understood, but there is an indication that contacts who are sero-positive for anti-PGL-I antibodies are at increased risk of developing clinical leprosy. The presence of a BCG scar is likely to be related to a lower risk. Analogies with tuberculosis suggest that the 'stone-in-the-pond' approach to control may be applicable to leprosy too. Sputum smear negative tuberculosis patients are known to spread the bacteria to others. This analogy strengthens the suggestion that the contacts of paucibacillary leprosy cases should also be included in contact tracing and examination. It is concluded that targeted interventions should be aimed at close contacts of both MB and PB patients inside and outside the household, particularly when genetically related.

A study on transmission and a trial of chemoprophylaxis in contacts of leprosy patients: design, methodology and recruitment findings of COLEP.

In this article, we describe the design, methodology and recruitment findings of the COLEP study. The objectives of this study were to determine the effectiveness of chemoprophylaxis with a single dose of rifampicin in the prevention of leprosy among close contacts of leprosy patients, and to find characteristics of contact groups most at risk to develop clinical leprosy. These characteristics should be usable by routine leprosy control programmes. COLEP consists of a cluster randomized, double-blind and placebo-controlled trial, a cohort study to determine risk factors characterizing the sub-groups most at risk within the total contact group of a patient, and a cohort study using a reference group from the general population to determine the prevalence and incidence of leprosy in the total population of the study area. The follow-up period will be 4 years. A coding system was developed describing the physical and genetic distance of the contact person to the patient. This study in Bangladesh includes 1037 newly diagnosed and previously untreated leprosy patients and their 21,867 contacts. The prevalence of leprosy among contacts was 7.3 per 1000. A total of 21,708 contacts without signs and symptoms of clinical leprosy are included in a trial of chemoprophylaxis with single dose rifampicin, and randomized at contact group level in treatment and placebo arms. The results of this large field trial will become available in the years to come.