Tuberculosis (TB) research has just received a much-needed cash injection. A donation of $82.9m from the Bill and Melinda Gates Foundation to support vaccine development more than doubles the annual amount spent on TB vaccines worldwide.

TB is an airborne, bacterial disease that claims almost 2 million lives every year. Some 2 billion people - one in three on the planet - are infected with the TB bacteria. One in 10 of those infected develops symptoms and becomes contagious.

TB can be treated with a cocktail of drugs, but these are expensive and are not available in many poorer countries. The existing Bacille Calmette-Guérin (BCG) vaccine slows disease progression but does not prevent infection. So researchers are developing new vaccines. Some are variants of BCG, designed to prompt a more efficient immune response. One such vaccine enters clinical trials next Tuesday, - after funding from the foundation.

"This is the first modified BCG vaccine to be tested in humans," says Daniel Hoft of St Louis University, Missouri, who is coordinating the trial with a centre in North Carolina.

The trial will assess whether the vaccine, called rBCG30, is safe. Fifteen people will receive the injection and be observed for nine months.