The world is one step closer to a vaccine for tuberculosis. Picture: David Ritchie/African News Agency (ANA)

New Delhi - An experimental tuberculosis vaccine has shown promising results in protecting half the people who received it, scientists said on Tuesday, marking a potential breakthrough in the fight against the world's most lethal infectious disease.

About 1.5 million people die of tuberculosis each year, meaning that even a vaccine with a partial success rate could have major impact.

The results of the trial were reported at a conference in Hyderabad, India, the country worst-affected by tuberculosis, and published in the New England Journal of Medicine.

The vaccine, was tested at 11 sites in Kenya, South Africa and Zambia in over 3 500 HIV-negative adults with latent tuberculosis infection, pharma giant GlaxoSmithKline said.

Half the adults received two doses of the vaccine and the rest received placebo shots. Thirteen people in the vaccine group and 26 in the placebo group developed active tuberculosis, it said.

The final results were consistent with the primary analysis done after two years of follow-up and published last year.

"We are one more cautious, but exciting step, close to a vaccine for TB," said Paula Fujiwara, scientific director of the International Union Against Tuberculosis and Lung Disease, which is hosting the conference.

Experts say additional trials need to be conducted to confirm these findings in other populations and the vaccine is still a few years from being licensed.

The current tuberculosis vaccine, the Bacillus Calmette-Guerin (BCG) jab, created in 1921, is frequently ineffective.

"These results demonstrate that for the first time in almost a century, the global community potentially has a new tool to provide protection against TB," Thomas Breuer, chief medical officer of GSK Vaccines said.

dpa