Much-hyped new TB vaccine fails clinical trials

Much-hyped new TB vaccine fails clinical trials

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By CHRISTABEL LIGAMI Special Correspondent

Posted Saturday, February 16 2013 in The East African


In Summary

•The findings on the MVA85A, which was hyped as the most advanced of more than a dozen currently under clinical trials, deal a major blow to the search for a new TB vaccine as the world’s second-biggest infectious killer disease continues to wreak havoc globally




A highly anticipated tuberculosis vaccine — the first in more than 90 years — offers no added benefits in protecting babies from infection over the current one, clinical trials show.


The findings on the MVA85A, which was hyped as the most advanced of more than a dozen currently under clinical trials, deal a major blow to the search for a new TB vaccine as the world’s second-biggest infectious killer disease continues to wreak havoc globally.


In East Africa, Kenya, Tanzania and Uganda are ranked among 45 high TB burden countries in that order. Kenya’s Ministry of Public Health says over 100,000 new cases were reported last year.


MVA85A was developed by researchers at the University of Oxford in the UK with support from Aeras, the Wellcome Trust, the European Commission and the Oxford-Emergent Tuberculosis Consortium, a joint venture between Oxford and Emergent Biosolutions Inc.


“We were hoping to see greater protection,” said Ann Ginsberg of Aeras.


Scientists embarked on developing a new TB vaccine because the current one — Bacille Calmette-Guérin (BCG), developed in 1921 — wears off in a few years, and does not protect against the most common form of tuberculosis that invades the lungs of adults and adolescents.


The researchers tested the MVA85A vaccine in nearly 3,000 healthy babies in South Africa who had already been given BCG. Half got the new vaccine while the other half served as the placebo group.


After a follow-up period of about two years, 32 babies in the MVA85A group had been infected with TB compared with 39 in the placebo group.


ALSO READ: Fight against TB fails children yet again - report


Researchers said the protection seen in the infants was much lower than that in adults, and they plan to look more closely to understand why. However, it was not reported how the vaccine worked in adults.


“This is the first efficacy trial of a new TB vaccine since BCG, and there is much that we and others can learn from the study,” said Helen McShane from the University of Oxford.


When predicting if a vaccine will work in humans, scientists often rely on animal models and protective markers in the blood known as correlates of protection This is not the case with TB, which hides in the cells of its human hosts.


As a result, TB vaccines must be tested in large clinical trials in people, a large and costly gamble.
 
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