A new study has explored the impact of six different rollout strategies by developing a mathematical model of tuberculosis (TB) transmission, care-seeking and diagnostic and treatment practices in India.
The researchers explained that while ideally all suspected TB cases would be evaluated with the new test, it was primarily being used only on the highest-risk populations and only in public health clinics, partly because of its cost and the complexity of the nation's health care system.
Approximately 8.6 million people worldwide develop active TB each year, and 1.4 million die from it. Twenty-five percent of all diagnosed TB patients are in India alone. Although treatment for TB is freely available and highly effective, TB continues to kill hundreds of thousands of people every year in India, and vast numbers of cases go undetected.
Public TB clinics are better equipped to quickly diagnose and begin treatment for the disease, but patients are often reluctant to utilize them. The researchers say that for better TB tests to make a major difference they must be made available to the private health care providers where patients first seek care.
The new test for TB, Xpert MTB/RIF, could diagnose TB in 90 minutes, capture 70 percent of cases missed by microscopy and could also determine if the strain was resistant to rifampin, the most important anti-TB drug. India has begun rolling out this new technology, but since Xpert MTB/RIF was much more expensive than traditional tests, it was currently being implemented mainly in public clinics to test HIV-positive patients who might also have TB or those at high risk of having multidrug-resistant tuberculosis (MDR-TB).
The study found that providing access to Xpert for 20 percent of all individuals seeking care for TB symptoms could reduce new TB cases by 14.1 percent over 5 years, while the "high-risk-only," public-sector strategy currently being implemented might only reduce TB cases by 0.2 percent. However, achieving this result required substantially more resources and appropriate TB treatment.
The researchers also found that simply improving the referral network of informal providers to the public sector without any new testing at all it could have as much of an effect on TB as scaling up the new Xpert test.
The study is published in the journal PLOS Medicine.
