Current vaccination for prevention of tuberculosis is limited to the bacille Calmette-Guerin (BCG) vaccine. It has prevented a large number of potential TB deaths each year, yet remains controversial due to its highly variable protection against pulmonary disease. The BCG vaccine has been administered since 1921 and after years of use in countries with high TB rates, its effectiveness at eradicating TB as a public health problem has been suboptimal [1]. While BCG vaccination in infants has been successful at reducing rates of disseminated disease in childhood, the vaccine is not equally effective in adults. As illustrated by Figure 1, incidence of TB in BCG vaccinated patients is increasing. Each year, there is a large population of infants
