Innovative Strategies and Challenges in Global Tuberculosis Control

• Delayed TB Diagnosis and Treatment: Many presumptive TB cases are not identified promptly, leading to diagnostic and treatment delays. Current reliance on the WHO symptom screen is due to the absence of better alternatives.
• TB Diagnostic Models: Studies focused on developing models using clinical predictors like history, physical examination, and chest radiography (CXR) to estimate PTB probability. More advanced imaging technologies were excluded due to their unavailability in high TB burden settings.
• Clinical Scores and Predictors: Six studies developed and validated models to improve PTB detection by incorporating factors such as CD4 count, BMI, and duration on antiretroviral therapy (ART). Adding the tuberculin skin test (TST) to the WHO symptom screen significantly improved sensitivity for detecting PTB.
• Need for Low-Cost TB Risk Scores: There is a highlighted need for a low-cost, easily applicable TB risk score to enhance screening accuracy and feasibility in high TB burden, low-resource settings.
• Global TB Control Targets: China likely cannot meet the current global targets for tuberculosis control by 2025. Achieving future targets, such as the 2035 goal of a 90% reduction in incidence and 95% reduction in mortality, appears even less attainable.
• Past Achievements in China: By 2010, China achieved older global targets of halving TB prevalence and mortality between 1990 and 2015. This success was driven by shifting TB treatment from hospitals to Chinese CDC public health centers.
• Challenges in Reducing TB Incidence: Future reductions in TB incidence and mortality are expected to be much slower. Active and enhanced surveillance may accelerate declines, but the benefits to individuals and communities are unclear.
• MDR Tuberculosis Control: MDR tuberculosis often results from person-to-person transmission. Improved prediction of MDR TB can lead to earlier diagnosis, better treatment outcomes, and reduced transmission risk. Including location-based data enhances MDR TB prediction.
• Strategies for Reducing MDR TB: Reducing MDR TB prevalence could be achieved by improving treatment of drug-susceptible TB and enhancing MDR TB diagnosis and treatment. A combination of these interventions could lead to a 75% decline in MDR TB prevalence over the decade starting in 2015.
• BCG Vaccination Considerations: Discontinuing the BCG vaccine could increase the TB burden, particularly in regions with high vaccine efficacy (VE). The immunity provided by BCG may wane over time, leaving the elderly less protected or not protected at all.
• Alternative to Stopping BCG Vaccination: Instead of completely stopping the BCG vaccination, selective vaccination could be a viable alternative. Improved early TB detection and prompt treatment might be more effective than BCG vaccination in controlling TB.
• Country-Specific TB Interventions: In South Africa, targeted interventions such as continuous isoniazid preventive therapy, expanded facility-based screening, and enhanced TB care could substantially reduce TB. For China and India, additional country-specific interventions, such as addressing latent TB in the elderly and combating undernutrition, are required to meet global TB targets.

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References:

1.     Van Wyk, S.S., Lin, H.H. and Claassens, M.M., 2017. A systematic review of prediction models for prevalent pulmonary tuberculosis in adults. The International Journal of Tuberculosis and Lung Disease, 21(4), pp.405-411.

2.     Lin, H.H., Wang, L., Zhang, H., Ruan, Y., Chin, D.P. and Dye, C., 2015. Tuberculosis control in China: use of modelling to develop targets and policies. Bulletin of the World Health Organization, 93, pp.790-798.

3.     Fu, H., Lin, H.H., Hallett, T.B. and Arinaminpathy, N., 2018. Modelling the effect of discontinuing universal Bacillus Calmette-Guérin vaccination in an intermediate tuberculosis burden setting. Vaccine, 36(39), pp.5902-5909.

4.     Houben, R.M., Menzies, N.A., Sumner, T., Huynh, G.H., Arinaminpathy, N., Goldhaber-Fiebert, J.D., Lin, H.H., Wu, C.Y., Mandal, S., Pandey, S. and Suen, S.C., 2016. Feasibility of achieving the 2025 WHO global tuberculosis targets in South Africa, China, and India: a combined analysis of 11 mathematical models. The Lancet Global Health, 4(11), pp.e806-e815.

5.     Lin HH, Shin SS, Contreras C, Asencios L, Paciorek CJ, Cohen T. Use of spatial information to predict multidrug resistance in tuberculosis patients, Peru. Emerg Infect Dis. 2012 May;18(5):811-3. doi: 10.3201/eid1805.111467.

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