By Jonathan Amos
BBC News Online science staff, in Seattle
A foundation set up by Microsoft chairman Bill Gates is giving away $83m to help fight tuberculosis.
Gates has given hundreds of millions of dollars to health charities
The disease, which is said by the World Health Organization to kill nearly 2m people each year, is developing forms that are now resistant to antibiotics.
The money will go to the Aeras Global TB Vaccine Foundation to fund current clinical trials and research new ideas.
"It's unacceptable that TB continues to kill someone every 15 seconds," Richard Klausner of the Gates Foundation said.
He announced the grant on the first day of the American Association for the Advancement of Science annual meeting here in Washington State.
Dr Marcos Espinal, executive secretary of the Stop TB Partnership, which is hosted by the WHO, welcomed Thursday's announcement.
"It is very significant. It is a great contribution by the Gates Foundation," he said. "There is a great need for new tools and this is certainly something which will produce major benefits."
The money should more than double the amount spent annually on TB vaccine research worldwide, said Dr Klausner, who is the executive director of the global health program at the Bill and Melinda Gates Foundation, as it is more properly known.
"We are in the midst of a new TB epidemic. The world desperately needs an effect vaccine to prevent TB, particularly in adolescents and adults.
Dr Jerald Sadoff: New approaches are promising
"Through accelerated research and development, a new vaccine could permanently change the trajectory of the epidemic and save millions of lives every year," he added.
Two billion people - one out of every three people on Earth - are infected with the TB pathogen, a bacterium called Mycobacterium tuberculosis.
Once in decline, the disease is now experiencing a resurgence, fuelled by the HIV/Aids epidemic. It is now the leading killer of people infected with the virus, and has also become the single biggest killer in developing nations of women aged between 15 and 44.
Another aspect in the resurgence of TB is the development of drug-resistant strains of the bacterium which now affect up to 50m people.
These strains are believed to have evolved as a result of bad medical practice, such as the over-prescribing of antibiotics, or through patients not taking the drugs long enough to get rid of the disease. This has allowed tougher bacteria to emerge.
A vaccine already exists - it is actually a family of vaccines called BCG (Bacille Calmette-Guerin) - but something more effective is needed in those countries where BCG is widely administered but the disease is still rampant.
The Aeras Global TB Vaccine Foundation is a non-profit organisation dedicated to developing new vaccine candidates. The money will be used to push new research through clinical trials and to improve some of the basic scientific tools used in laboratory studies.
The grant will also help develop new vaccine production and distribution networks.
Dr Jerald Sadoff is the president and chief executive officer of Aeras.
He said: "We are hoping over the next two to three years to push the leading candidate vaccines into a position where they can be tested for efficacy so that we can get licensure and delivery of vaccines in the next seven to 10 years."
The two leading candidates are now in phase 1 clinical trials. The first is known as rBCG30 and is an enhanced version of the BCG vaccine that has been genetically engineered to stimulate a stronger immune response.
The second, a "fusion protein", is a combination of two proteins from the TB pathogen that are primary targets of the immune system. The aim is to use both candidates together, to first prime the immune system and then boost it.
"This prime-boost approach has shown remarkable protection, especially in primates, which has never been seen before," said Dr Sadoff.