TB kills around 2 million people every year. Credit: © WHO

Tuberculosis (TB) research has just received a much-needed cash injection. A donation of US$82.9 million 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 out of every three people on the planet - are already infected with the TB bacteria. One in 10 of those infected develop symptoms and become contagious.

The disease is already rife in the developing world, but it's also on the up in the North America and Europe. Sufferers commonly experience respiratory problems and can cough up blood. The World Health Organization estimates that over the next 20 years, 36 million people will die from the disease unless it is brought under control.

TB can be treated with a cocktail of drugs, but these are expensive and are not available in many poorer countries. The existing vaccine - known as Bacille Calmette-Guérin (BCG) - slows disease progression but does not prevent infection.

So researchers are developing a range of new vaccines. Some are variants of the BCG vaccine, designed to prompt a more efficient immune response. On such vaccine enters clinical trials next Tuesday - thanks to funding from the Bill and Melinda Gates Foundation.

TB drugs are expensive and often unavailable in poor countries. Credit: © WHO

"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 to use in humans. Fifteen people will receive the injection and be observed for a period of nine months. If the vaccine proves safe, it will be tested in larger numbers of people.

Other vaccines are also being tested by research centres around the world. One, known as a fusion protein, combines two proteins from the TB bacterium. It is hoped that the protein hybrid will be more easily recognized by the immune system, prompting a better immune reaction than with other vaccines.

Our goal is to license and deliver a more effective TB vaccine within ten years Jerald Sadoff , President, Gates Foundation

"The vaccines may work well in combination," says Hoft. Modified BCG vaccines could be given at birth and then followed up with the fusion-protein vaccine.

Different delivery methods could also help to improve the vaccines' efficacy, says Hoft. At present, the BCG vaccine is injected under the skin, but it could be introduced more directly to the lungs by delivering it by mouth or nose.

The new funding will be distributed by the Aeras Global TB Vaccine Foundation, a non-profit-making organization that helps to coordinate vaccination development on a global scale.

The money will help to push existing vaccines through clinical trials, and also assist the development the next generation of vaccines, says Jerald Sadoff, the foundation's president. "Our goal is to license and deliver a more effective TB vaccine within ten years," he says.