Vijayakumaran P, Krishnamurthy P, Rao P, Declerq E
Damien Foundation India Trust, Chetput, Chennai, India.
Lepr Rev. 2000 Dec;71 Suppl:S37-40; discussion S40-1. doi: 10.5935/0305-7518.20000065.
Because of the great efficacy of multidrug therapy (MDT), it had been hoped that the widespread use of MDT would bring about a rapid decrease of the incidence of leprosy. To the present, a decrease of incidence has not been observed, possibly because of the long incubation period of the disease, and because general implementation of MDT is still recent. Other reasons, such as environmental sources of infection or the role of healthy carriers in transmitting Mycobacterium leprae, cannot be excluded. Therefore, one must seek alternative or supplementary strategies, such as chemoprophylaxis. Household contacts of leprosy patients are at greater risk of developing leprosy than is the general population. Therefore, a randomized, controlled trial of chemoprophylaxis, using a single 10 mg/kg dose of rifampicin, or a placebo, is planned in nine projects in India, among the household contacts of newly detected leprosy patients. Based upon assumptions of a protective efficacy of the chemoprophylaxis of 50%, an annual incidence of 2 per 1000 contacts, a desired power of the study of 90%, and a level of significance of 95%, 15,000 household contacts will be allocated randomly by household to each arm of the study, and followed for 5 years. Considered as household contacts will be all persons living in the same household as an index case and sharing the same kitchen. Pregnant women and infants will be excluded. To be certain that transmission of the organisms from the index case cannot occur once the prophylaxis is administered, rifampicin will be administered 2 months after diagnosis of the index case. Diagnosis of leprosy will be clinical, and confirmed independently. Although household contacts usually constitute only a small proportion of the new patients detected in a control programme, their high-risk status makes them particularly appropriate for a study of the potential effect of chemoprophylaxis. Following the trial, one could evaluate the usefulness and feasibility of using the same strategy in other population-groups, based on the number of persons necessary to treat to prevent one case.
由于多药联合疗法（MDT）疗效显著，人们曾希望广泛使用MDT能使麻风发病率迅速下降。到目前为止，尚未观察到发病率下降，可能是因为该病潜伏期长，且MDT的全面实施仍为时不久。其他原因，如感染的环境源或健康携带者在传播麻风杆菌中的作用，也不能排除。因此，必须寻求替代或补充策略，如化学预防。麻风患者的家庭接触者比一般人群患麻风的风险更高。因此，计划在印度的九个项目中，对新发现麻风患者的家庭接触者进行一项随机对照试验，使用单次10mg/kg剂量的利福平或安慰剂进行化学预防。基于化学预防保护效力为50%、每年每1000名接触者发病率为2、研究所需效能为90%以及显著性水平为95%的假设，将15000名家庭接触者按家庭随机分配到研究的每个组，并随访5年。被视为家庭接触者的将是与索引病例居住在同一家庭且共用同一厨房的所有人。孕妇和婴儿将被排除。为确保一旦给予预防措施，索引病例的病原体就不会传播，利福平将在索引病例诊断后2个月给予。麻风的诊断将基于临床，并独立确认。虽然家庭接触者通常只占控制项目中新发现患者的一小部分，但他们的高风险状态使他们特别适合进行化学预防潜在效果的研究。试验结束后，可以根据预防一例所需治疗的人数，评估在其他人群中使用相同策略的有用性和可行性。
