The best vaccine against tuberculosis is also the only vaccine against tuberculosis, and it's not a great one at that. Called BCG, it protects many children, but it fails miserably in shielding adults.
By genetically modifying the weakened bacterium that makes up BCG, European scientists working with mice have developed a vaccine that seems to offer better protection than BCG does. They report their work in the Sept. 1 Journal of Clinical Investigation.
BCG is shorthand for bacille Calmette-Guérin, the bacterium that bears the names of the two scientists who created the vaccine by weakening a strain of cattle tuberculosis in 1921. The advent of antibiotics since then has largely enabled industrialized countries to control TB without the vaccine. But BCG is widely used in developing countries: 3 billion people have received it.