Ng Han Guan/Associated Press
Published: September 3, 2012
RelatedA new study has confirmed, once again, that hard-to-cure drug-resistant tuberculosis is a growing problem.
Two years ago, the World Health Organization released a study with an equally pessimistic outlook.
About a third of the world has latent tuberculosis, experts estimate; it usually becomes active when an infected person’s immune system is depressed.
The most dangerous forms still tend to concentrate in alcoholics, prisoners, heavy smokers, the unemployed and homeless, people with H.I.V. — and particularly in people who previously had active TB but did not cure it. But now some patients, especially in former Soviet-bloc countries, are catching strains that already are resistant to some antibiotics.
Curing resistant TB can cost 200 times as much as curing typical TB; it can also take years, and some of the drugs cause side effects like deafness and psychosis.
New drug combinations that might cure some cases in less than a month and that do not clash ith H.I.V. drugs are being tested by the nonprofit TB Alliance. While no new TB vaccine has been developed since 1921, a dozen potential candidates are in clinical trials, according to Aeras, a nonprofit organization specializing in vaccines