Despite setback, TB vaccine study is a step in the right direction

For more than 90 years, the world has relied on a less-than-perfect tuberculosis vaccine to protect against the contagious lung infection. Bacille Calmette-Guérin is routinely given to babies in countries with high rates of TB, but the jab wears off after a few years and doesn't protect against the most common form of the disease.

Researchers want to find a shot that will put an end to the approximately 1.4 million deaths from TB recorded every year. And while a closely watched study of Bill & Melinda Gates Foundation-backed TB vaccine MVA85A failed to produce the desired results to guard against infection in infants, a dozen more vaccine candidates are being tested in humans. Regardless of results, the first efficacy trial of a new TB vaccine is a milestone.

Researchers tested MVA85A, developed by researchers at the University of Oxford with support from Aeras, the Wellcome Trust, the European Commission and the Oxford-Emergent Tuberculosis Consortium, in nearly 3,000 healthy babies in South Africa who had already received the BCG vaccine. Half got the new vaccine and half got a placebo. Two years later, 32 babies in the MVA85A group got TB compared with 39 in the placebo group. The improvement was insignificant statistically.

Despite a lackluster outcome, the study itself is an important step in the search for a more effective vaccine.

"Although the results of this first efficacy trial of a new TB vaccine are not what we had hoped for, further analysis of the data should reveal a great deal about how the body's immune system protects against TB and what is necessary to develop an effective vaccine," said senior author professor Helen McShane, a Wellcome Trust Senior Clinical Research Fellow at the University of Oxford and the original developer of the vaccine. "The results from this study should let us know far more about the type and level of immune response required, and that will boost future efforts to develop an effective TB vaccine by Oxford and other researchers throughout the world. The difficulty of this task is one reason why there has not been a new TB vaccine since BCG was developed more than 90 years ago, but one is still urgently needed and I'm not about to give up now."

Aeras is backing 6 TB vaccine candidates and two more from Johnson & Johnson's ($JNJ) Crucell vaccines unit and GlaxoSmithKline ($GSK) in large-scale trials.

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