BCG tuberculosis vaccine found effective

OXFORD, England, Oct 13, 2005 (UPI via COMTEX) -- University of Oxford scientists say they've determined BCG vaccination can protect children from tuberculosis infection as well as active TB disease.

The researchers say there are about 10 million cases of TB globally each year and 1-in-3 people are infected with the TB bacterium. BCG -- Bacillus Calmette-Guerin -- vaccine is the most widely used vaccine worldwide, but its mechanism of protection is poorly understood.

The effect of BCG vaccine has been difficult to ascertain because, until recently, the only method for detecting infection was the tuberculin skin-prick test. But TST cannot distinguish between TB infection and BCG vaccination.

In the latest study researchers used a more accurate T-cell based blood test along with TST to assess infection.

The scientists investigated risk factors for TB infection in 979 children, all sharing a household with at least one adult with TB. Of those children, 770 had a BCG scar.

The researchers found the absence of a scar was a strong, independent risk factor for infection in TB-exposed children, while the presence of a BCG scar was associated with a 24 percent reduction in infection risk.

The study appears in the current issue of The Lancet.

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