April 8 (HealthDay News) -- An experimental tuberculosis vaccine called MVA85A proved safe in a small phase I clinical trial.

The study included 12 people with latent tuberculosis infection, which, when re-activated, can cause full-blown TB. It's believed that about a third of the world's population has this latent infection. The participants, who had no other complicating factors, such as hepatitis or HIV, were given the vaccine and then followed for a year.

The researchers concluded that the vaccine was safe, did not produce any immunopathology and was immunogenic in the patients. Some participants had side effects that included fever, headache, fatigue and mild concerns at the site of the vaccination.

The findings appear in the April 15 issue of the American Journal of Respiratory and Critical Care Medicine.

This study could be an important step forward in efforts to introduce a new vaccine to fight TB, according to the researchers, led by Dr. Helen McShane, of the University of Oxford in England. They noted that any new vaccine must be developed with latent TB infection in mind because it might decrease the effectiveness of new vaccines or worsen vaccine-related side effects.

"A more effective vaccine regimen than the currently available bacillus Calmette-Guerin would have a major impact on the global TB burden and, ultimately, will be the most efficient way to control this pandemic," the researchers wrote.

They noted that larger trials of the vaccine "are needed in TB endemic areas to assess the efficacy of this vaccine against the development of TB disease, but these results are very encouraging and justify the further development of this vaccine."

SOURCE: American Thoracic Society, news release, April 7, 2009