Vaccine Shows Promise For Preventing Active TB Disease |

An experimental vaccine has proved 50% effective at preventing latent tuberculosis infection from turning into active disease in a three-year study of adults in Africa.

Even a partially effective vaccine would still help fight TB. The lung disease kills more than a million people a year and about one-third of the world's people harbor the bacteria that cause it.

There is a TB vaccine now, but it's given only to very young children and partly prevents severe complications. Researchers have been seeking a vaccine that also works in adults, to curb spread of the disease.

GlaxoSmithKline's experimental vaccine was tested in nearly 3,600 adults in Africa. Results were reported Tuesday at a conference in India and published by the New England Journal of Medicine.