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DEVELOPMENT REPORT - June 17, 2002: New TB Vaccine to be Tested
By Jill Moss
This is the VOA Special English Development Report.
Scientists are preparing to test the safety of a new vaccine medicine that could protect people against tuberculosis. Earlier this month, researchers at the World Congress on Tuberculosis in Washington, D.C., announced the testing. It is to begin by the end of this year in San Francisco, California. This will be the first time in nearly eighty years that a new vaccine has been tested against T-B.
Researchers say the new vaccine is a form of an old vaccine called B-C-G. This vaccine is only partly effective in preventing the disease. It is used in developing countries to prevent severe tuberculosis in children. However, B-C-G does not protect adults from the disease.
About two-million people die from T-B each year. Currently, about one-third of the world's population is infected with the bacteria that cause tuberculosis. Their infection is inactive. T-B infection can remain inactive in a person's lungs for years, or even a lifetime. The disease becomes active in about ten percent of all cases.
T-B causes a high body temperature and coughing. Infected people spread the disease by releasing particles from their mouths when they cough, sneeze, spit or talk. Someone with active T-B must take medicine each day for six to nine months to halt progression of the disease.
The World Health Organization has a five-step program to guarantee that T-B patients take their medicine correctly. The program is called Directly Observed Treatment, Short-Course, or DOTS. Health officials are working hard to expand the program around the world. However, only twenty-seven percent of all tuberculosis cases are discovered and treated within the DOTS program. Health experts say a new vaccine to prevent T-B is very important.
The last new drug to treat T-B was created more than forty years ago. Since that time, different forms of the disease have become resistant to drugs currently being used. However, researchers believe this is about to change because of the discovery of the genetic structure of the bacterium that causes the disease.
That discovery four years ago has helped scientists better understand how T-B bacteria work. It also has given researchers information to help them develop new drugs and vaccines.
This VOA Special English Development Report was written by Jill Moss.
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