Community-randomized trial of enhanced DOTS for tuberculosis control in Rio de Janeiro, Brazil.

Detection of cases and institution of effective chemotherapy is considered the most important strategy for controlling tuberculosis (TB), and is the cornerstone of global public health efforts.1 The World Health Organization’s (WHO’s) DOTS Strategy2 is widely followed, but has had variable success in reducing TB incidence rates in developing countries and in settings with a high prevalence of human immunodeficiency virus (HIV) infection.3,4 The TB epidemic in developing countries demands evaluation of broader approaches in addition to DOTS. Evaluation of contacts of TB cases is integral to control efforts in industrialized countries, but is little used in high-burden settings. Routine contact evaluation usually yields a small proportion of active TB cases and varying proportions of contacts with latent TB infection (LTBI).5 Chemoprophylaxis of LTBI with isoniazid (INH) reduces the risk of subsequent TB disease in high-risk household contacts and HIV-infected people.6 Recent TB transmission contributes to a large proportion of active TB cases in urban settings.7–9 Mathematical models have suggested that preventive therapy, in combination with DOTS, may contribute substantially to TB control efforts.10,11 We undertook a cluster-randomized trial to assess the impact of a TB control strategy that included evaluation and treatment of contacts of newly diagnosed TB patients on the community incidence of TB in Rio de Janeiro City, Brazil. Enhanced DOTS (DOTS-Ampliado or DOTS-A) added intensive screening of household contacts of active TB cases and provision of TB treatment to secondary cases and preventive therapy to contacts with LTBI to the standard DOTS program.