Reactivation of tuberculosis after apparently adequate chemoprophylaxis

Screening of the close contacts of patients with pulmonary tuberculosis remains an important component in the control and prevention of the disease. It is carried out to identify active and latent infection, and those requiring BCG vaccination. Guidelines suggest giving chemoprophylaxis to asymptomatic contacts with a positive Heaf test (grades 2-4) and normal chest radiograph [Control and prevention of tuberculosis in the United Kingdom: code of practice 2000. Joint Tuberculosis Committee of the British Thoracic Society. Thorax 2000;55:887-901]. We report a case involving a close contact where current guidelines were followed, but failed to prevent subsequent development of active disease from the same strain of M. tuberculosis.