Tuberculosis preventive treatment: the next chapter of tuberculosis elimination in India

Evaluating the cost-effectiveness of Cy-Tb for LTBI in India: a comprehensive economic modelling analysis

BACKGROUND

Latent tuberculosis infection (LTBI) remains a significant challenge, as there is no gold standard diagnostic test. Current methods used for identifying LTBI are the interferon-γ release assay (IGRA), which is based on a blood test, and the tuberculin skin test (TST), which has low sensitivity. Both these tests are inadequate, primarily because they have limitations with the low bacterial burden characteristic of LTBI. This highlights the need for the development and adoption of more specific and accurate diagnostic tests to effectively identify LTBI. Herein we estimate the cost-effectiveness of the Cy-Tb test as compared with the TST for LTBI diagnosis.

METHODS

An economic modelling study was conducted from a health system perspective using decision tree analysis, which is most widely used for cost-effectiveness analysis using transition probabilities. Our goal was to estimate the incremental cost and number of TB cases prevented from LTBI using the Cy-Tb diagnostic test along with TB preventive therapy (TPT). Secondary data such as demographic characteristics, treatment outcome, diagnostic test results and cost data for the TST and Cy-Tb tests were collected from the published literature. The incremental cost-effectiveness ratio was calculated for the Cy-Tb test as compared with the TST. The uncertainty in the model was evaluated using one-way sensitivity analysis and probability sensitivity analysis.

RESULTS

The study findings indicate that for diagnosing an additional LTBI case with the Cy-Tb test and to prevent a TB case by providing TPT prophylaxis, an additional cost of 18 658 Indian rupees (US$223.5) is required. The probabilistic sensitivity analysis indicated that using the Cy-Tb test for diagnosing LTBI was cost-effective as compared with TST testing. If the cost of the Cy-Tb test is reduced, it becomes a cost-saving strategy.

CONCLUSIONS

The Cy-Tb test for diagnosing LTBI is cost-effective at the current price, and price negotiations could further change it into a cost-saving strategy. This finding emphasizes the need for healthcare providers and policymakers to consider implementing the Cy-Tb test to maximize economic benefits. Bulk procurements can also be considered to further reduce costs and increase savings.

Advancing tuberculosis elimination in India: A qualitative review of current strategies and areas for improvement in tuberculosis preventive treatment

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a global health challenge, despite being preventable and curable. The global goal to end TB by 2030, with India targeting a 90% reduction in TB incidence by 2025, demands comprehensive interventions in prevention, early detection, treatment, and capacity building. This study analyzes the 2023 Global TB Reports, published articles, guidelines, and data to explore India's current TB landscape. Despite progress in diagnostics and TB preventive treatment, significant challenges persist in accessibility, adherence, and treatment completion. Although advancements in household contact screening and TB preventive treatment initiation are notable, gaps in reporting, diagnostic algorithms, and adherence remain. Innovative diagnostic tools and shorter treatment regimens show promise but require more comprehensive implementation. India's strategy for TB elimination focuses on policy expansion, community engagement, and system enhancements. Continuous innovation, rigorous evaluation, and collaborative efforts are crucial to overcoming challenges and meeting TB elimination targets.

TB prevention and immunization in pediatrics

Tuberculosis (TB) is one of the main contributors to global mortality and morbidity. Prevalence of TB is more in developing countries. It is one of the airborne diseases that has always been a major health problem. It is caused by organisms of the Mycobacterium tuberculosis (MTB) complex affecting different organ systems. The proverb prevention is better than cure best applies to TB and it has been practiced from ancient periods. However, modalities of prevention have varied much depending upon the advancement in research and technology. TB preventive practice reduces the load of TB significantly and it was used as the theme for world TB Day for the year 2013. Bacille Calmette-Guérin (BCG) vaccination is one of the modalities to prevent TB and it's been practiced for decades with a lot of modifications from synthesis, schedule and method of administration. BCG mainly prevents serious TB with a less known effect on TB prevention. Other uses of BCG vaccination are being studied. In the modern era, heterologous effects of BCG vaccination have brought BCG once again into the limelight. TB prevention strategies start from basic health education and vaccination. Newer vaccines are under trial to improve the efficacy of TB vaccination and yet to be used for general practice. Prevention and immunization against TB have been modified in immunocompromised children. The concept of drug resistance has to be kept in mind before using anti tubercular drugs without any bacteriological evidence for tuberculosis. National Tuberculosis Elimination Programme (NTEP) focuses on contact tracing and treatment of latent TB infection as a resort to prevent further spread of TB in India. This review article has been authored following an exhaustive examination of the existing literature, with the aim of enhancing comprehension regarding tuberculosis prevention and immunization.

Test and treat approach for tuberculosis infection amongst household contacts of drug-susceptible pulmonary tuberculosis, Mumbai, India

Background

Mumbai is one of the most densely populated areas in the world and is a major contributor to the tuberculosis (TB) epidemic in India. A test and treat approach for TB infection (TBI) amongst household contacts (HHC) is part of the national policy for TB preventive treatment (TPT). However, in practice, the use of interferon-gamma release assay (IGRA) tests for infection are limited, and prevalence of TBI in Mumbai is not known.

Methods

We conducted a cross-sectional study among HHCs exposed to persons with microbiologically-confirmed, drug-susceptible pulmonary TB that were notified for antituberculosis treatment in Mumbai, India during September-December, 2021. Community-based field workers made home visits and offered IGRA (QuantiFERON-TB® Gold In-Tube Plus) tests to HHC aged 5 years and older. After ruling out active TB disease, HHC with IGRA-positive test results were referred for TPT. All HHC were monitored for at least 24 months for progression to active TB disease.

Results

Among 502 HHCs tested, 273 (54%) had IGRA-positive results. A total of 254 (93%) were classified as TBI and were eligible for TPT, of which 215 (85%) initiated TPT, and 194 (90%) completed TPT successfully. There was substantial variation in rates of TBI per household. In 32% of households, all HHC (100%) were IGRA positive and in 64% of households >50% of HHC were infected. In all, 22 HHCs (4%; 22/558) were diagnosed with TB disease; of these, five HHC were diagnosed during follow up, of which three were IGRA positive and had no evidence of disease at initial screening but chose not to initiate TPT.

Conclusion

A test and treat strategy for HHC resulted in the detection of a substantial proportion of TBI and secondary TB cases. Home-based IGRA testing led to high participation rates, clinical evaluations, TPT initiation, and early diagnoses of additional secondary cases. A community-focused, test and treat approach was feasible in this population and could be considered for broader implementation.

Outcomes and Challenges in the Programmatic Implementation of Tuberculosis Preventive Therapy among Household Contacts of Pulmonary TB Patients: A Mixed-Methods Study from a Rural District of Karnataka, India

The National TB Elimination Programme (NTEP) of India is implementing tuberculosis preventive treatment (TPT) for all household contacts (HHCs) of pulmonary tuberculosis patients (index patients) aged <5 years and those HHCs aged >5 years with TB infection (TBI). We conducted an explanatory mixed-methods study among index patients registered in the Kolar district, Karnataka during April-December 2022, to assess the TPT cascade and explore the early implementation challenges for TPT provision. Of the 301 index patients, contact tracing home visits were made in 247 (82.1%) instances; a major challenge was index patients' resistance to home visits fearing stigma, especially among those receiving care from the private sector. Of the 838 HHCs, 765 (91.3%) were screened for TB; the challenges included a lack of clarity on HHC definition and the non-availability of HHCs during house visits. Only 400 (57.8%) of the 692 eligible HHCs underwent an IGRA test for TBI; the challenges included a shortage of IGRA testing logistics and the perceived low risk among HHCs. As HHCs were unaware of their IGRA results, a number of HHCs actually eligible for TPT could not be determined. Among the 83 HHCs advised of the TPT, 81 (98%) initiated treatment, of whom 63 (77%) completed treatment. Though TPT initiation and completion rates are appreciable, the NTEP needs to urgently address the challenges in contact identification and IGRA testing.

Innovating tuberculosis prevention to achieve universal health coverage in the Philippines

To contribute to tuberculosis (TB) elimination, TB preventive treatment (TPT) should integrate innovative approaches including tele-contact investigation (TCI), mathematical modelling, and participatory governance. Aligning with the World Health Organisation's primary health care framework, supply is provided by the provincial health system, demand is cultivated by the community, while governance is represented by the governor, who oversees the health leadership structure, local policies, and allocation of resources. A healthy dynamic between these three components is required to achieve universal health coverage (UHC). Because of their potential to integrate health systems and engage communities, primary health care principles underpin an effective approach to TB prevention. First, the provincial health system should connect with the community through TCI to transform the status quo of passive service delivery. Second, community participation should strengthen the linkage between the health system and governance, which ensures that community action plans are aligned with provincial TPT targets. Third, governance should leverage mathematical modelling to allocate resources to those with greatest need. Central to this is a reliable TB information system that should validate a robust mathematical model to measure cost-effectiveness of the intervention. Collectively, this holistic approach to TB prevention could provide a proof-of-concept that investing in primary health care is the key to UHC.

Prioritising attributes for tuberculosis preventive treatment regimens: a modelling analysis

BACKGROUND

Recent years have seen important improvements in available preventive treatment regimens for tuberculosis (TB), and research is ongoing to develop these further. To assist with the formulation of target product profiles for future regimens, we examined which regimen properties would be most influential in the epidemiological impact of preventive treatment.

METHODS

Following expert consultation, we identified 5 regimen properties relevant to the incidence-reducing impact of a future preventive treatment regimen: regimen duration, efficacy, ease-of-adherence (treatment completion rates in programmatic conditions), forgiveness to non-completion and the barrier to developing rifampicin resistance during treatment. For each regimen property, we elicited expert input for minimally acceptable and optimal (ideal-but-feasible) performance scenarios for future regimens. Using mathematical modelling, we then examined how each regimen property would influence the TB incidence reduction arising from full uptake of future regimens according to current WHO guidelines, in four countries: South Africa, Kenya, India and Brazil.

RESULTS

Of all regimen properties, efficacy is the single most important predictor of epidemiological impact, while ease-of-adherence plays an important secondary role. These results are qualitatively consistent across country settings; sensitivity analyses show that these results are also qualitatively robust to a range of model assumptions, including the mechanism of action of future preventive regimens.

CONCLUSIONS

As preventive treatment regimens against TB continue to improve, understanding the key drivers of epidemiological impact can assist in guiding further development. By meeting these key targets, future preventive treatment regimens could play a critical role in global efforts to end TB.

Incidence of tuberculosis among PLHIV on antiretroviral therapy who initiated isoniazid preventive therapy: A multi-center retrospective cohort study

Introduction

Isoniazid preventive therapy (IPT) is effective in treating tuberculosis (TB) infection and hence limiting progression to active disease. However, the durability of protection, associated factors and cost-effectiveness of IPT remain uncertain in low-and-middle income countries, Uganda inclusive. The Uganda Ministry of health recommends a single standard-dose IPT course for eligible people living with HIV (PLHIV). In this study we determined the incidence, associated factors and median time to TB diagnosis among PLHIV on Antiretroviral therapy (ART) who initiated IPT.

Materials and methods

We conducted a retrospective cohort study at eleven The AIDS Support Organization (TASO) centers in Uganda. We reviewed medical records of 2634 PLHIV on ART who initiated IPT from 1^st January 2016 to 30^th June 2018, with 30^th June 2021 as end of follow up date. We analyzed study data using STATA v.16. Incidence rate was computed as the number of new TB cases divided by the total person months. A Frailty model was used to determine factors associated with TB incidence.

Results

The 2634 individuals were observed for 116,360.7 person months. IPT completion rate was 92.8%. Cumulative proportion of patients who developed TB in this cohort was 0.83% (22/2634), an incidence rate of 18.9 per 100,000 person months. The median time to TB diagnosis was 18.5 months (minimum– 0.47; maximum– 47.3, IQR: 10.1–32.4). World Health Organization (WHO) HIV clinical stage III (adjusted hazard ratio (aHR) 95%CI: 3.66 (1.08, 12.42) (P = 0.037) and discontinuing IPT (aHR 95%CI: 25.96(4.12, 169.48) (p = 0.001)), were associated with higher odds of TB diagnosis compared with WHO clinical stage II and IPT completion respectively.

Conclusion

Incidence rates of TB were low overtime after one course of IPT, and this was mainly attributed to high completion rates.

Prevalence and risk factors associated with latent tuberculosis infection among household contacts of smear positive pulmonary tuberculosis patients in South India

OBJECTIVE

We aimed to determine the prevalence and find the risk factors associated with latent tuberculosis infection (LTBI) among the household contacts (HHC) of pulmonary TB patients.

METHODS

This cohort study was conducted from 2014 to 2019. Pretested standardised questionnaires and tools were used for data collection. The prevalence of LTBI among HHCs of TB patients was summarised as proportion with 95% confidence interval (CI). Mixed-effects generalised linear modelling function (meglm) in STATA with family Poisson and log link was performed to find the factors associated with LTBI.

RESULTS

In total, 1523 HHC of pulmonary TB patients were included in the study. Almost all HHC shared their residence with the index case (IC) for more than a year; 25% shared the same bed with the IC. The prevalence of LTBI among the HHC of TB patients was 52.6% (95% CI: 50.1-55.1%). In an adjusted model, we found that among HHC belonging to the age group of 19-64 years (aIRR = 1.2; 95% CI: 1.1-1.3; p-value: 0.02), to the age group >65 years (aIRR = 1.4, 95% CI: 1.1-1.9, p-value: 0.02) and sharing the same bed with the IC (aIRR = 1.2, 95% CI: 1.1-1.3, p value: 0.04) were independent determinants of LTBI among the HHC.

CONCLUSION

One in two household contacts of TB patients have latent tuberculosis infection. This underscores the need of targeted contact screening strategies, effective contact tracing and testing using standardised methods in high TB burden settings.

Impact of Effective Global Tuberculosis Control on Health and Economic Outcomes in the United States

Rationale: Most U.S. residents who develop tuberculosis (TB) were born abroad, and U.S. TB incidence is increasingly driven by infection risks in other countries.

Objectives: To estimate the potential impact of effective global TB control on health and economic outcomes in the United States.

Methods: We estimated outcomes using linked mathematical models of TB epidemiology in the United States and migrants’ birth countries. A base-case scenario extrapolated country-specific TB incidence trends. We compared this with scenarios in which countries achieve 90% TB incidence reductions between 2015 and 2035, as targeted by the World Health Organization’s End TB Strategy (“effective global TB control”). We also considered pessimistic scenarios of flat TB incidence trends in individual countries.

Measurements and Main Results: We estimated TB cases, deaths, and costs and the total economic burden of TB in the United States. Compared with the base-case scenario, effective global TB control would avert 40,000 (95% uncertainty interval, 29,000–55,000) TB cases in the United States in 2020–2035. TB incidence rates in 2035 would be 43% (95% uncertainty interval, 34–54%) lower than in the base-case scenario, and 49% (95% uncertainty interval, 44–55%) lower than in 2020. Summed over 2020–2035, this represents 0.8 billion dollars (95% uncertainty interval, 0.6–1.0 billion dollars) in averted healthcare costs and $2.5 billion dollars (95% uncertainty interval, 1.7–3.6 billion dollars) in productivity gains. The total U.S. economic burden of TB (including the value of averted TB deaths) would be 21% (95% uncertainty interval, 16–28%) lower (18 billion dollars [95% uncertainty level, 8–32 billion dollars]).

Conclusions: In addition to producing major health benefits for high-burden countries, strengthened efforts to achieve effective global TB control could produce substantial health and economic benefits for the United States.

Assessment of knowledge, attitude and practice on tuberculosis among teacher trainees of Samtse College of Education, Bhutan

Background

Tuberculosis (TB) is a major public health problem in Bhutan despite the implementation of directly observed treatment short-course since 1997. This study aimed to assess the knowledge, attitude and practice on TB among the teacher trainees of Samtse College of Education.

Methodology

A cross-sectional study was conducted among the teacher trainees of Samtse College of Education. A standardized pretested questionnaire was distributed and self-administered. The participants were selected randomly using randomization. The data was entered in Epi-data 4.4.2.1 and analysed using STATA version 13. A score of 1 point for a correct answer and 0 for wrong/don’t know answer was given. The knowledge, attitude and practice score were divided into good and poor based on 50% cut off. Logistic regression was used for the analysis to identify the significant covariates.

Results

A total of 420 trainees responded to the survey questionnaire. The average knowledge score on TB was 10.7 (Range = 0–21). Two hundred and forty respondents (58.6%) had low knowledge (mean score 7.8±2.5) on TB. Cough, chest pain and weight loss were correctly reported as the symptoms of TB by 306 (72.9%), 187(44.5%) and 187 (44.5%) participants. Eighty-nine-point five percent (376) of participants reported coughing as the main route of TB transmission and 85% (357) of the participants said that it could be prevented by covering the mouth while coughing. In multivariable analysis; the trainees in the junior years of college had good knowledge of TB compared with the senior years (adjusted odds ratio [AOR] 2.02; 95% confidence interval [CI] 1.18–3.5; p-value 0.011). Respondents previously treated for TB were more likely to have good knowledge on TB compared to those who never had TB in the past (AOR 2.39; 95% CI 1.07–5.31; p-value 0.033). The majority (93%) of respondents had a good attitude towards TB cases. Female trainees were 2.4 (95% CI 1.02–5.62; p-value 0.045) times more likely than male trainees to have a positive attitude towards TB. Eighty-eight percent of the respondents reported that they would visit the hospital if they had TB symptoms. The mean score for the practice on TB was 1.33±0.59 (Range:0–2).

Conclusion

In this study, the majority of the trainees had poor knowledge on TB, especially among the trainees in senior years of college and those who had never suffered from TB. The attitude towards TB was good especially among the female trainees. However, the overall practice was poor among the participants. Therefore, the Ministry of Health should collaborate with relevant stakeholders especially the Ministry of Education to incorporate topics on TB in the syllabus of students and colleges to create awareness on it.

Status and challenges for tuberculosis control in India - Stakeholders' perspective

BACKGROUND

Tuberculosis is one of the ten major causes of mortality worldwide. The trend of increasing TB cases and drug resistance in India is very disturbing. The objectives of the study were to study the perspectives and opinions of different stakeholders on the status, challenges and the ways to tackle the issues of TB in India.

METHODS

The online survey was done for the data collection from national and international experts. The data collection took place during October 2017. We received 46 responses.

RESULTS

The experts had varied answers as to the menace of TB in India, effect of TB on individuals, family and society, failure of government plans in India, TB awareness campaign and ways to create awareness. Everyone believed that urgent action needs to be taken against the disease like improving the healthcare infrastructure of the country (improving the quality and quantity of medical facilities and doctors) and creating awareness about the TB.

CONCLUSION

Government of India is making lot of efforts to bring down the problems associated with TB through. In spite of this, there is a long way to go to achieve significant reduction in high incidence and prevalence of TB in India. Factors like lack of awareness and resources, poor infrastructure, increasing drug resistant cases, poor notification and overall negligence are the major challenges. If we eradicate poverty and undernourishment, educate the masses and eliminate the stigma attached with TB, we can hope for a disease free future.

R, Suryavanshi N, B. M. S, Cox SR, Selvaraju S, Gupte N, Mave V, Gupta A, Bollinger RC. Tuberculosis preventive treatment should be considered for all household contacts of pulmonary tuberculosis patients in India

The World Health Organization (WHO) recently changed its guidance for tuberculosis (TB) preventive treatment (TPT) recommending TPT for all pulmonary TB (PTB) exposed household contacts (HHC) to prevent incident TB disease (iTBD), regardless of TB infection (TBI) status. However, this recommendation was conditional as the strength of evidence was not strong. We assessed risk factors for iTBD in recently-exposed adult and pediatric Indian HHC, to determine which HHC subgroups might benefit most from TPT. We prospectively enrolled consenting HHC of adult PTB patients in Pune and Chennai, India. They underwent clinical, microbiologic and radiologic screening for TB disease (TBD) and TBI, at enrollment, 4–6, 12 and 24 months. TBI testing was performed by tuberculin skin test (TST) and Quantiferon®- Gold-in-Tube (QGIT) assay. HHC without baseline TBD were followed for development of iTBI and iTBD. Using mixed-effect Poisson regression, we assessed baseline characteristics including TBI status, and incident TBI (iTBI) using several TST and/or QGIT cut-offs, as potential risk factors for iTBD. Of 1051 HHC enrolled, 42 (4%) with baseline TBD and 12 (1%) with no baseline TBI test available, were excluded. Of the remaining 997 HHC, 707 (71%) had baseline TBI (TST ≥ 5 mm or QGIT ≥ 0.35 IU/ml). Overall, 20 HHC (2%) developed iTBD (12 cases/1000 person-years, 95%CI: 8–19). HIV infection (aIRR = 29.08, 95% CI: 2.38–355.77, p = 0.01) and undernutrition (aIRR = 6.16, 95% CI: 1.89–20.03, p = 0.003) were independently associated with iTBD. iTBD was not associated with age, diabetes mellitus, smoking, alcohol, and baseline TBI, or iTBI, regardless of TST (≥ 5 mm, ≥ 10 mm, ≥ 6 mm increase) or QGIT (≥ 0.35 IU/ml, ≥ 0.7 IU/ml) cut-offs. Given the high overall risk of iTBD among recently exposed HHCs, and the lack of association between TBI status and iTBD, our findings support the new WHO recommendation to offer TPT to all HHC of PTB patients residing in a high TB burden country such as India, and do not suggest any benefit of TBI testing at baseline or during follow-up to risk stratify recently-exposed HHC for TPT.

The potential impact of preventive therapy against tuberculosis in the WHO South-East Asian Region: a modelling approach

BACKGROUND

The prevention of tuberculosis (TB) is key for accelerating current, slow declines in TB burden. The 2018 World Health Organization (WHO) guidelines on eligibility for preventive therapy to treat latent TB infection (LTBI) include people living with human immunodeficiency virus (PLHIV), household contacts of TB patients including children, and those with clinical conditions including silicosis, dialysis, transplantation, etc. and other country-specific groups. We aimed to estimate the potential impact of full implementation of these guidelines in the WHO South-East Asian (SEA) Region, which bears the largest burden of TB and LTBI amongst the WHO regions.

METHODS

We developed mathematical models of TB transmission dynamics, calibrated individually to each of the 11 countries in the region. We modelled preventive therapy in the absence of other TB interventions. As an alternative comparator, reflecting ongoing developments in TB control in the region, we also simulated improvements in the treatment cascade for active TB, including private sector engagement and intensified case-finding. Relative to both scenarios, for each country in the region, we projected TB cases and deaths averted between 2020 and 2030, by full uptake of preventive therapy, defined as comprehensive coverage amongst eligible populations as per WHO guidelines, and assuming outcomes consistent with clinical trials. We also performed sensitivity analysis to illustrate impact under less-than-optimal conditions.

RESULTS

At the regional level, full uptake of preventive therapy amongst identified risk groups would reduce annual incidence rates in 2030 by 8.30% (95% CrI 6.48-10.83) relative to 2015, in the absence of any additional interventions. If implemented against a backdrop of improved TB treatment cascades, preventive therapy would achieve an incremental 6.93 percentage points (95% CrI 5.81-8.51) of reduction in annual incidence rates, compared to 2015. At the regional level, the numbers of individuals with latent TB infection that need to be treated to avert 1 TB case is 64 (95% CrI 55-74). Sensitivity analysis illustrates that results for impact are roughly proportional to 'effective coverage' (the product of actual coverage and effectiveness of the regimen).

CONCLUSIONS

Full implementation of WHO guidelines is important for ending TB in the SEA Region. Although future strategies will need to be expanded to the population level, to achieve large declines in TB incidence, the uptake of current tools can offer a valuable step in this direction.

History of household member with tuberculosis or related death in newly diagnosed patients in India

Among new smear-positive pulmonary tuberculosis (TB) patients aged ⩾15 years from marginalised populations in India, one in four had a history of a household member with TB and one in 10 had a TB-related death in the household. This contribution of household transmission to overall TB transmission provides evidence for a potential population-level benefit of TB preventive treatment for all household contacts (without active TB). Females with TB had a significantly higher household TB exposure than males. Targeted TB preventive treatment (if implemented in a phased manner) among female household contacts may be explored after considering other factors.

Strategies for ending tuberculosis in the South-East Asian Region: A modelling approach

Background & objectives:

To support recent political commitments to end tuberculosis (TB) in the World Health Organization South-East Asian Region (SEAR), there is a need to understand by what measures, and with what investment, these goals could be reached. These questions were addressed by using mathematical models of TB transmission by doing the analysis on a country-by-country basis in SEAR.

Methods:

A dynamical model of TB transmission was developed, in consultation with each of the 11 countries in the SEAR. Three intervention scenarios were examined: (i) strengthening basic TB services (including private sector engagement), (ii) accelerating TB case-finding and notification, and (iii) deployment of a prognostic biomarker test by 2025, to guide mass preventive therapy of latent TB infection. Each scenario was built on the preceding ones, in successive combination.

Results:

Comprehensive improvements in basic TB services by 2020, in combination with accelerated case-finding to increase TB detection by at least two-fold by 2020, could lead to a reduction in TB incidence rates in SEAR by 67.3 per cent [95% credible intervals (CrI) 65.3-69.8] and TB deaths by 80.9 per cent (95% CrI 77.9-84.7) in 2035, relative to 2015. These interventions alone would require an additional investment of at least US$ 25 billion. However, their combined effect is insufficient to reach the end TB targets of 80 per cent by 2030 and 90 per cent by 2035. Model projections show how additionally, deployment of a biomarker test by 2025 could end TB in the region by 2035. Targeting specific risk groups, such as slum dwellers, could mitigate the coverage needed in the general population, to end TB in the Region.

Interpretation & conclusions:

While the scale-up of currently available strategies may play an important role in averting TB cases and deaths in the Region, there will ultimately be a need for novel, mass preventive measures, to meet the end TB goals. Achieving these impacts will require a substantial escalation in funding for TB control in the Region.