Feasibility and Effectiveness of Community Based Isoniazid Preventive Therapy in Kenya

Isoniazid preventive therapy (IPT) is a well studied clinical intervention for primary and secondary prevention of active tuberculosis (TB) after infection with Mycobacterium tuberculosis. It is widely used in industrialized countries in TB outbreak management, focusing on high risk groups such as close contacts in the family, in congregate settings, and in the workplace amongst others. Individuals infected with Human Immunodeficiency Virus (HIV) have a markedly higher risk of acquiring a TB-infection and developing consequently active TB, making HIV-infected individuals a target population for IPT. Studies of IPT in HIV infected persons in the nineties demonstrated the efficacy of IPT in the prevention of active TB in Sub -Saharan Africa and more recent studies suggest that the protective effect remains present in individuals on antiretroviral therapy. Despite the proven efficacy of IPT this intervention has not been taken up by most HIV and TB control programmes in Africa where the burden of TB/HIV is highest. The reasons for the low uptake of IPT are many and varied but include fears of expansion of isoniazid resistance and subsequently the development of multi -drug resistant TB with widespread use of IPT. Additionally screening protocols for excluding active TB and selecting persons for IPT have not been uniformly agreed upon. There have also been concerns that programmes designed to provide IPT may shift TB control programmes from their primary responsibility of finding and treating active TB. Finally it has been unclear as to which programme, between the HIV and the TB control programme, has the primary responsibility of managing the provision of the IPT intervention. The World Health Organization and other technical agencies engaged in global TB control have recently re-emphasized the need to scale up IPT. In this proposal we outline an operational research study to evaluate the introduction of IPT at community level and to measure its effectiveness at pre