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TB vaccine takes a tumble

A leading candidate for a sorely needed new vaccine against tuberculosis (TB) has failed to protect children against the disease in a major clinical trial.

Published today in The Lancet, the results of the trial of the MVA85A vaccine show that it seems to have “no significant efficacy” against either TB or infection with Mycobacterium tuberculosis.

The results are a major blow to the TB research community, as MVA85A had seemed highly promising as a solution to the problem of the patchy efficacy of the ‘BCG’ vaccine used worldwide against the disease.

It was hoped that the new vaccine could be used as a booster to the BCG. A team led by Helen McShane of Oxford University in the UK and Hassan Mahomed of Stellenbosch University in South Africa gave MVA85A to 1,399 infants in South Africa and gave placebos to a further 1,398. Thirty-nine of the placebo group and 32 of those given the new vaccine developed TB. And 171 infants in the placebo group became infected with M. tuberculosis, versus 178 of those vaccinated.

In a statement, McShane said, “The vaccine induced modest immune responses against TB in the infants, but these were much lower than those previously seen in adults, and were insufficient to protect against the disease. This is the first efficacy trial of a new TB vaccine since [the BCG], a significant step in itself, and there is much that we and others can learn from the study and the data it has produced.”

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