A community-wide screening program being trialled in Vietnam aims to create a new model for global TB control
In the 1950s and 1960s Australians were accustomed to having regular chest x-rays in a caravan, parked in their suburb, to screen for TB. During this time TB almost (but not quite) disappeared from Australia and the program was phased out.
Now Australian researchers from the Centenary Institute, Woolcock Institute of Medical Research and the Centre of Research Excellence on TB Control will assess the potential for a similar program of regular community-wide screening to have the same impact on TB in Vietnam, a country in which TB is still very common and costs many lives. However, instead of x-rays the team will use a new molecular test that is performed on sputum coughed up from patient’s lungs to detect TB.
They hope their work will serve as a model for countries with a high burden of TB in our region and elsewhere.
“While Vietnam has a good TB treatment program, it can only help people who have been diagnosed with TB. The limiting factor in reducing the burden of TB in Vietnam, and other similar countries, is finding all the cases of TB,” says Dr Guy Marks, a researcher at the Woolcock Institute of Medical Research in Sydney.
In a recent survey in Vietnam, it was estimated that around 350 people out of every 100,000 people have TB at any given time. “There are several reasons that TB cases are not diagnosed: the non-specific nature of the symptoms or lack of symptoms in some cases, the stigma surrounding the disease, and the various alternative sources of health care that are available in Vietnam,” says Dr Marks.
These types of misdiagnosis arise because the conventional x-ray screening approach is too difficult, expensive and open to misinterpretation. By screening all adults within the area, the program is expected to reveal many cases of TB that wouldn’t have been diagnosed otherwise.
“X-ray screening in challenging in developing countries,” says Dr Marks. “You either have to move the person to the x-ray or you have to move the x-ray to the person.”
X-ray equipment is bulky and expensive and difficult to transport to these remote villages, many of which don’t have the roads to accommodate medical vans. Even less practical is sending thousands of working adults to their local x-ray machine which may be hours of travel away.
Beginning in April and running over the next four years, the project team will screen 60,000 people for the deadly disease, visiting 60 villages in Vietnam’s southern provinces annually.
“The true marker of success for the project will be if, after four years, we can show a reduction in the prevalence of TB,” says Dr Marks.
At the heart of the project is a technology that is making TB detection faster, more convenient and more accessible. The test, called GeneXpert™, is performed on a sample of sputum. Developed with the support of the Bill and Melinda Gates Foundation, the test can give results in under two hours, meaning samples can be collected and analysed quickly without inconveniencing communities.
It’s hoped that this screening program will serves as a model to implement in other TB burdened regions such as PNG and the Ningxia Hui Autonomous Region in China where other Centenary Institute led research into TB is being conducted.
The program is a collaboration between Australian researchers and the Vietnamese government and is funded by the National Health and Medical Research Council of Australia.
View full media release here.
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