The first new tuberculosis vaccine result in a century

Every attempt at a better adult vaccine in the century since had failed to show clear protection. Researchers testing M72/AS01E, developed by GSK with Aeras, enrolled adults in Kenya, South Africa, and Zambia already latently infected with the tuberculosis bacterium, the group most likely to develop active disease.

Over three years of follow-up, the vaccine was about 50 percent effective at preventing progression to active pulmonary tuberculosis compared with placebo, among the first candidates in nearly a hundred years of trying to show meaningful protection against the disease's most dangerous, contagious form in adults.

Fifty percent protection is far from complete, and the trial was not large enough to be the final word before wider rollout. The nonprofit Gates Medical Research Institute later took over the vaccine's development to run the larger, confirmatory trial needed for approval, a process still underway, in a disease that still kills more than a million people a year worldwide.

A century of failed vaccines, then one that showed protection.