A closely watched study of a new Gates-backed tuberculosis vaccine--MVA85A--failed to deliver desperately hoped-for data that it could guard infants against the lethal disease. Widely considered to be the best shot at the first new TB vaccine in close to a century, investigators said the jab failed to prove that it had a comparable effect as that seen in a study involving adults.
"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," Oxford University's Helen McShane told The Guardian. The failure is a bitter setback against a concerted effort to come up with a better vaccine than Bacille Calmette-Guérin, or BCG, which can't stop the 1.4 million deaths recorded every year for TB.
Researchers engaged in the study concluded that the vaccine delivered nonsignificant efficacy measured at 17.3%.
The failure may be a setback in the ambitious effort to develop a new vaccine, but it is by no means a death knell for research efforts. Investigators say a dozen TB vaccines are being tested in humans to stop the scourge, with dozens more in the lab to follow. Some other studies are also still under way for MVA85A,which may still offer big gains in protecting adults. And despite the failure, scientists say there is plenty to be learned from this failure as investigators push ahead on new research efforts.
"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," McShane said in a statement. "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."