A new test to quickly diagnose drug-resistant forms of tuberculosis will be rolled out in four African countries this year, the World Health Organization said Monday.
The DNA-based test will cut the time it takes to detect multi-drug resistant TB from 2-4 months to a matter of hours, the director of WHO’s tuberculosis program said in Geneva.
Dr. Mario Raviglione said testing is currently “one of the major bottlenecks” in combating the disease, which becomes harder to treat the longer patients have to wait for the appropriate medication.
“This test is feasible, is affordable, and is effective in high endemic countries,” said Giorgio Roscigno of the Geneva-based Foundation for Innovative New Diagnostics, which helped develop the test.
Medical aid group Medecins Sans Frontieres welcomed the new speedier diagnosis, but said it remains to be seen how cost-effective the test will be.
More than 9 million people around the world fall sick with tuberculosis every year. Of those, about 500,000 get multi-drug resistant TB, which is immune to two types of antibiotic treatment. Patients with drug-resistant tuberculosis have to switch to more potent and expensive medicines.
Improving survival
Detecting drug-resistant TB quickly improves the chances a patient will survive and lowers the risk that the disease mutates further into an even more drug-resistant form of the disease. Extensively drug-resistant tuberculosis, which affects about 40,000 people each year, is very difficult to treat with drugs. It has become a major threat to HIV patients in Africa, as well as among prison populations in the ex-Soviet countries of Eastern Europe.
The Stop TB Partnership — an umbrella group created to bring together different organizations in the fight against the disease — said it will train staff and equip laboratories in four African countries this year, starting with the small southern African nation of Lesotho.
Ethiopia, Ivory Coast and Congo will also begin using the $5 test before the end of the year, said Raviglione. A further $15 has to be spent on lab equipment and staff salaries, bringing the total cost to $20 compared with up to $34 for older methods.
However, training staff to carry out the tests will be a major challenge, said Dr. Tido von Schoen-Angerer of Medecins Sans Frontieres, also known as Doctors Without Borders. New labs and trained staff will be needed to run the tests, since TB is highly infectious and must be handled carefully, so the overall cost of the test is still unclear.
“The problems with the test are that they are very, very complex,” he said. “The desperate search for much simpler tests has to continue, but this at least is a good step forward in cutting down the time to diagnosis.”
Von Schoen-Angerer also said the new test is still unable to detect extensively drug resistant tuberculosis and cannot be used for patients who either cannot cough up any sputum or who appear to have no bacteria in their sputum. About half of HIV-positive patients with TB are “sputum negative,” meaning the new test will not work for them.
WHO said it hopes the test will be introduced in 16 African countries over the next four years.
Dr. Karin Weyer, a South African TB expert who reviewed the new tests for WHO, acknowledged the limitations but maintained that they can be overcome.
“The test is as reliable, if not more reliable, than the conventional test that we have now,” she said.
WHO’s Mario Raviglione said he expects even rich countries to switch to the new DNA-tests in future because they are so fast.