This is an early access version, the complete PDF, HTML, and XML versions will be available soon. Open AccessReview by Anja Reuter 1 and Jennifer Furin 2,* 1 The Sentinel Project on Pediatric Drug-Resistant Tuberculosis, Cape Town 7405, South Africa 2 Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115, USA * Author to whom correspondence should be addressed.