Abstract
Current international guidelines recommend 6-9 months of isoniazid (INH) preventive chemotherapy to prevent the development of active tuberculosis in children exposed to a susceptible strain of M tuberculosis. However, this is dependent on good adherence and retrospective studies have indicated that adherence to unsupervised INH preventive chemotherapy is poor. To prospectively document adherence to six months of unsupervised INH monotherapy and outcome in children with household exposure to an adult pulmonary tuberculosis index case. From February 2003 to January 2005 in two suburbs of Cape Town, South Africa, all children or =5 months of unsupervised INH monotherapy. During the subsequent surveillance period six children developed tuberculosis: two received no preventive chemotherapy, and four had very poor adherence. Adherence to six months of unsupervised INH preventive chemotherapy was poor. Strategies to improve adherence, such as using shorter duration multidrug regimens and/or supervision of preventive treatment require further evaluation, particularly in children who are at high risk to progress to disease following exposure.