New vaccine offers hope of tuberculosis breakthrough

Scientists believe they have made a breakthrough in the development of a new vaccine against tuberculosis which kills an estimated 1.7m people in the world each year.

The existing vaccine, bacile Calmette-Guerin (BCG), provides some protection against childhood forms of the infection but is unreliable against the adult lung disease, which is steadily spreading.

Professor William Jacobs of Albert Einstein College of Medicine in New York has devised a prototype vaccine against the TB microbe, Mycobacterium tuberculosis.

Professor Jacobs and his colleagues deleted a set of genes called ESX-3 from the mouse bacterium and substituted them with ESX-3 genes of the human infectious agent. Mice inoculated with the new strain survived infection with TB microbes.

"Most notably, those vaccinated animals that survived for more than 200 days had livers that were completely clear of TB bacteria, and nobody has ever seen that before.

"We don't even know yet if it will work in humans, but it's certainly a significant step in efforts to create a better TB vaccine," Professor Jacobs said.

The study was published in the journal Nature Medicine.