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article imageNew TB vaccine doesn't work on infants

By Tim Sandle     Feb 9, 2013 in Health
A new tuberculosis vaccine, heralded as the world's most advanced, has been shown not to work on infants following trials in South Africa.
The vaccine was developed at Oxford University and is called MVA85A (for Modified Vaccinia Ankara 85A). It was launched in 2009 and was claimed to be the most advanced tuberculosis vaccine yet developed. The vaccine was designed to replace the mainstay of TB vaccines, BCG (Bacillus Calmette–Guérin), which is routinely given to newborns. BCG was introduced in 1921.
The MVA85A passed rigorous safety checks and appeared to be effective. However, now that the results of tests on 2,800 infants in South Africa, who had already been given a BCG shot, between 2009 and 2011, have been analyzed the new vaccine's efficacy rate is only around 17 percent. With the test, half of the infants were given the new vaccine and half were given a non-active placebo.
The low rating is because of those given the vaccine, 32 developed TB compared to 39 from the group who were given the placebo (this type of trial is commonplace when conducting an 'evidence based' medicine trial; this one was described as a "double-blind, randomised, placebo-controlled phase 2b trial").
Prof Helen McShane, from the University of Oxford, who developed the vaccine, is quoted by the BBC as saying: "[It] 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 Bacille Calmette-Guérin, a significant step in itself, and there is much that we and others can learn from the study and the data it has produced."
The study was paid for by Aeras, the Wellcome Trust and the Oxford-Emergent Tuberculosis Consortium. The results were published in the journal Lancet.
More about Tb, Tuberculosis, Vaccine, Africa, Infants