Globally significant findings from Sydney scientists and their Vietnamese colleagues, published today in the prestigious New England Journal of Medicine, show a pathway towards the eventual elimination of TB.
Work by Professor Guy B. Marks of the Woolcock Institute of Medical Research, and Associate Professor Greg J. Fox of the University of Sydney has demonstrated that annual community-wide screening for tuberculosis almost halves the number of TB infections.
The study, which screened 100,000 people in Vietnam, showed this method was 44 per cent more effective than the standard passive case detection method. Importantly, the trial halved rates of TB infection among school-aged children.
“We believe our study shows a pathway towards TB elimination.”
“Our findings show that, with existing tests and treatments used in innovative ways, we can achieve the sort of impact on TB that makes it possible to consider the elimination of this disease,” says study leader, Woolcock epidemiologist Professor Guy Marks. “With community-wide screening we can interrupt the cycle of active disease and infection that perpetuates the deadly tuberculosis epidemic. This is the key to the eventual elimination of TB.”
More than 10 million people are infected with tuberculosis and 1.8 million people die from it every year. There are more deaths due to tuberculosis than any other infectious disease. Rates are highest in India, followed by Indonesia, China, Philippines, Pakistan, Nigeria, and South Africa. Vietnam is also in the top 20 countries.
There are more deaths due to tuberculosis than any other infectious disease
TB is a lung infection that is curable with medication, but many people are not diagnosed and treated in time to prevent spread to others. As a result, TB rates in many low- and middle-income nations are at epidemic proportions and the World Health Organization’s goal to eliminate the disease by 2030 looks increasingly unlikely.
Currently, the main approaches to TB control are passive case detection, which relies on people with symptoms of TB seeking and finding effective TB care, and targeted active case finding, in which certain high-risk groups are screened for TB disease. However, these two approaches are inadequate because many people who have infectious forms of TB have few, if any symptoms. Those who do have symptoms often find it difficult to navigate their way through the health system to get effective care. Furthermore, in countries with a high burden of TB, most people with TB are not in so-called high risk groups – everyone is at risk of TB. For these reasons, the current global strategies for TB control are not making much progress towards to TB elimination.
"...this approach is... not limited to those who seek care for symptoms... it bypasses health system weaknesses."
“We reasoned that, if there are few or no people with untreated TB disease to infect others, there will be few or no new infections and, ultimately, no new cases,” Professor Marks says. “The important feature of this approach is that it’s not limited to those who seek care for symptoms or to the minority of cases who are in ‘high risk’ groups, and it bypasses health system weaknesses.”
The study has shown that screening for TB among all adult residents of a community, annually for three years, results in a nearly 50 per cent reduction in people with the disease. Additionally, there was a 50 per cent lower prevalence of TB infection in children aged six to 14 years. “Impressive global targets for ending TB will not be met with the current strategy,” Professor Marks says. “We believe our study shows a pathway towards TB elimination.”
Further research is needed in different settings before the approach can be rolled out nationally in countries with high TB burden, Professor Marks says. Also, more work is needed to optimise the tools and methods of implementing the screening intervention.
This trial was the first ever using this intervention
The trial was conducted in a Mekong delta province in Vietnam with a high burden of TB. Half of the communities were screened as part of the study and the other half were a non-intervention comparison population that had full access to local health screening upon voluntary presentation to clinics and hospitals. Screening as part of the trial involved collecting sputum from people in their homes and testing the specimen using a molecular test for TB. This trial was the first ever using this intervention.
The study was funded by the Australian National Health and Medical Research Council and is a close collaboration between researchers in Australia and Vietnam. The paper, ‘Community-wide Screening for Tuberculosis in a High-Prevalence Setting’, can be viewed here on the New England Journal of Medicine website.
Professor Guy Marks is available for interview on (+61)419 251 565
His email is guy.marks@sydney.edu.au
His profiles are at https://sydney.edu.au/medicine-health/about/our-people/academic-staff/guy-marks.html and https://med.unsw.edu.au/people/professor-guy-marks
TB: The Facts [1]
Tuberculosis is one of the top 10 causes of death worldwide
In 2016, 10.4 million people fell ill with TB, and 1.8 million died from the disease
There is a risk of further spread of multi-drug resistant TB, which is challenging to treat
Over 95 per cent of TB deaths occur in low- and middle-income countries
Each year an estimated 1 million children became ill with TB and 250,000 children died of TB
About 53 million lives were saved through TB diagnosis and treatment between 2000 and 2016
What does TB mean for Australia?
Most cases in the world are in our region (Asia-Pacific or Indo-Pacific)
Migration and travel, two major issues for Australia, mean that TB in our region is a Health Security problem we cannot ignore
Economic development among our trading partners is seriously impacted by the burden of TB in their countries.
1 in 20 Australians are latent ‘carriers’ of TB and Indigenous Australians are 6-times more likely to develop disease than non-indigenous Australian-born individuals
[1] From the World Health Organization website: http://www.who.int/mediacentre/factsheets/fs104/en/
About the Woolcock and the TB-CRE
The Woolcock Institute of Medical Research is one of the world's leading respiratory and sleep research organisations. It has more than 200 medical researchers working to uncover the causes of disease, find better treatments and translate these into practice.
The Centre of Research Excellence in Tuberculosis Control (TB-CRE) is a research collaboration centre which develops, tests, and implements TB elimination strategies in Australia and the Asia-pacific region.
TB-CRE investigators and associates involved in this study include Professor Guy B. Marks, Associate Professor Greg J. Fox, Professor Warwick J. Britton, Dr Thu-Anh Nguyen, Dr Paul H. Mason, Dr Jennifer Ho, Associate Professor Vitali Sintchenko, and a number of others.