A new trial to test the efficacy of a tuberculosis (TB) booster shot for babies is about to start in South Africa, but when your subjects are too young to eat solids, the challenge rises to a new level. Almost 2,800 infants will participate in the two-year trial, in which researchers from the South African Tuberculosis Vaccine Initiative (SATVI) hope to prove that a new vaccine can act as a booster shot to improve the efficacy of the only existing inoculation against TB, the Bacille Calmette-Guerin (BCG) vaccine, in use for nearly 90 years.