A new vaccine against TB, which initially showed much promise, has not proven effective for infants in the last phase of clinical trials, says an article, by David Brown, in the Washington Post:
The study, reported online by the Lancet on Monday, was conducted in about 2,800 South African infants. Although the vaccine did not protect them, it might possibly benefit adolescents or adults. “We’re disappointed that the trial did not have a positive outcome,” said Tom Evans, a physician who heads Aeras, the nonprofit biotechnology company in Rockville that developed the vaccine. He added, “We can’t necessarily say this kind of vaccine is not going to be efficacious in another population.”
About a third of the dozen tuberculosis vaccines in human testing bear some biological resemblance to Aeras’s product, MVA85A. The study results are unlikely to stop work on the other “candidate” vaccines, at least immediately. Evans and others sought to put the best spin on the results. In a Lancet commentary, two experts said the study “presents the tuberculosis vaccine community with a serious challenge” but is “at last generating hard evidence about protection against tuberculosis.”
The experiment, run in the rural outskirts of Cape Town, produced data that were both detailed and unambiguous. That is an achievement in itself, Evans said. “We got a very clean answer that will help us move forward,” he said.
Aeras has six TB vaccines in clinical trials and a larger number in laboratory development. About 8.7 million people became ill with tuberculosis in 2011, the latest year for which there are complete statistics, and 1.4 million died. The bacterium Mycobacterium tuberculosis is carried by about one-third of the globe’s population, according to some estimates. Transmission is usually through the air, with the organism infecting the lungs. In most people the infection is “latent,” controlled by the body’s immune defenses.
Although this news is disappointing and a setback to coming up with a viable and effective vaccine, this does not suggest that the vaccine in some form will not work for older children or adults. This would be a partial victory. Of course, it's important that an efficacious vaccine for infants eventually be developed—one that would help eradicate TB from the list of known diseases.
You can read the rest of the article at [Washington Post].