Jane E. Hughes

One third of the global population is estimated to be latently infected with Mycobacterium tuberculosis. We performed a phase I randomized controlled trial of isoniazid preventive therapy (IPT) before revaccination with bacillus Calmette–Guérin (BCG) in healthy, tuberculin skin test–positive (≥15-mm induration), HIV-negative South African adults. We hypothesized that preclearance of latent bacilli with IPT modulates BCG immunogenicity following revaccination.