Wednesday, October 27, 2004

Good News/Bad News About TB

Tuberculosis (Wikipedia Merck Manual) is a bacterial disease that has successfully resisted attempts to control it.  I wrote about the problem of multidrug-resistant TB, back in March.  Now there is more bad news:

TB poses major threat to millions
Tuesday, 26 October, 2004

Tuberculosis will continue to kill millions in developing countries unless radical action is taken, an aid organisation has warned.

TB can be easily treated, but Medecins San Frontieres says inadequate attempts to control the disease mean it is now spiraling out of control.

MSF says drug-resistant strains, coupled with HIV pose a major threat.

The charity is calling for massive investment in developing new diagnostic tests and drugs.
For once, though, there is good news:
New TB vaccine shown to be safe
Sunday, 24 October, 2004

The first TB vaccine to be developed in more than 80 years has passed safety trials in the UK.

Oxford University researchers say the vaccine could boost the power of the existing BCG vaccine.

The study, in Nature Medicine, suggests the new vaccine could be of particular use in the developing world, where cases of tuberculosis are rising.

The World Health Organization estimates one person is infected every second. It kills two million people annually.

It is believed to be present in about one-third of the world's population, around two billion people, although many people do not develop the disease.

In England, the number of cases of TB has risen by 25% over the last decade.

The BCG vaccine is thought to offer protection for around 15 years.

But it is not effective for everyone. In the UK, only around two thirds of those who receive the vaccination are believed to be protected. Some trials have suggested protection could be as low as 30%.

The new MVA85A vaccine was tested in Oxford, where schoolchildren no longer routinely receive BCG.

The three-year study, which was funded by the Wellcome Trust research charity, involved 42 adults aged 18 to 55, who were divided into three groups.

Two groups had never been vaccinated with BCG. One of these was given BCG and the other MVA85A.

People in the third group, who had previously received BCG, were given MVA85A as a boost.

In those who were only given MVA85A, the trials showed it was safe and produced a high number of T 'helper' cells, which fight disease.

Those who had previously had BCG and were given MVA85A revealed a far greater number of T cells, in some case up to 30 times the levels produced in the other groups. [...]

Dr McShane said MVA85A appeared to work as an "ally" with BCG, rather than as a replacement.

"BCG induces low levels of T cells. So when you later give MVA85A the cells are reminded of the disease and build a bigger barrier to TB."
The abstract of the original article is available here, as an advance online publication of Nature Medicine.  Although a clinically usable vaccine probably will take years to develop, the fact that the study was published online in advance of the print edition suggests that the medical community feels that this is a highly significant finding.