Tuberculosis control in China: use of modelling to develop targets and policies

Spatiotemporal analysis and seasonality of tuberculosis in Pudong New Area of Shanghai, China, 2014-2023

BACKGROUND

Spatiotemporal analysis is a vital method that plays an indispensable role in monitoring epidemiological changes in diseases and identifying high-risk clusters. However, there is still a blank space in the spatial and temporal distribution of tuberculosis (TB) incidence rate in Pudong New Area, Shanghai. Consequently, it is crucial to comprehend the spatiotemporal distribution of TB in this district, this will guide the prevention and control of TB in the district.

METHODS

Our research used Geographic Information System (GIS) visualization, spatial autocorrelation analysis, and space-time scan analysis to analyze the TB incidence reported in the Pudong New Area of Shanghai from 2014 to 2023, and described the spatiotemporal clustering and seasonal hot spot distribution of TB incidence.

RESULTS

From 2014 to 2023, the incidence of TB in the Pudong New Area decreased, and the mortality was at a low level. The incidence of TB in different towns/streets has declined. The spatial autocorrelation analysis revealed that the incidence of TB was spatially clustered in 2014, 2016-2018, and 2022, with the highest clusters in 2014 and 2022. The high clustering area was mainly concentrated in the northeast. The space-time scan analysis indicated that the most likely cluster was located in 12 towns/streets, with a period of 2014-2018 and a radiation radius of 15.74 km. The heat map showed that there was a correlation between TB incidence and seasonal variations.

CONCLUSIONS

From 2014 to 2023, the incidence of TB in the Pudong New Area of Shanghai declined, but there were spatiotemporal clusters and seasonal correlations in the incidence area. Local departments should formulate corresponding intervention measures, especially in high-clustering areas, to achieve accurate prevention and control of TB within the most effective time and scope.

Global analysis of an age-structured tuberculosis model with an application to Jiangsu, China

Diagnostic delay for TB infected individuals and the lack of TB vaccines for adults are the main challenges to achieve the goals of WHO by 2050. In order to evaluate the impacts of diagnostic delay and vaccination for adults on prevalence of TB, we propose an age-structured model with latent age and infection age, and we incorporate Mycobacterium TB in the environment and vaccination into the model. Diagnostic delay is indicated by the age of infection before receiving treatment. The threshold dynamics are established in terms of the basic reproduction number R 0 . WhenR 0 < 1 , the disease-free equilibrium is globally asymptotically stable, which means that TB epidemic will die out; WhenR 0 = 1 , the disease-free equilibrium is globally attractive; there exists a unique endemic equilibrium and the endemic equilibrium is globally attractive whenR 0 > 1 . We estimate that the basic reproduction numberR 0 = 0.5320 (95% CI (0.3060, 0.7556)) in Jiangsu Province, which means that TB epidemic will die out. However, we find that the annual number of new TB cases by 2050 is 1,151 (95%CI: (138, 8,014)), which means that it is challenging to achieve the goal of WHO by 2050. To this end, we evaluate the possibility of achieving the goals of WHO if we start vaccinating adults and reduce diagnostic delay in 2025. Our results demonstrate that when the diagnostic delay is reduced from longer than four months to four months, or 20% adults are vaccinated, the goal of WHO in 2050 can be achieved, and 73,137 (95%CI: (23,906, 234,086)) and 54,828 (95%CI: (15,811, 206,468)) individuals will be prevented from being infected from 2025 to 2050, respectively. The modeling approaches and simulation results used in this work can help policymakers design control measures to reduce the prevalence of TB.

Nonlinear neural networks adaptive control for a class of fractional-order tuberculosis model

The problem of nonlinear adaptive control for a class of fractional-order tuberculosis (TB) model is studied in this paper. By analyzing the transmission mechanism of TB and the characteristics of fractional calculus, a fractional-order TB dynamical model is established with media coverage and treatment as control variables. With the help of universal approximation principle of radial basis function neural networks and the positive invariant set of established TB model, the expressions of control variables are designed and the stability of error model is analyzed. Thus, the adaptive control method can guarantee that the number of susceptible and infected individuals can be kept close to the corresponding control targets. Finally, the designed control variables are illustrated by numerical examples. The results indicate that the proposed adaptive controllers can effectively control the established TB model and ensure the stability of controlled model, and two control measures can protect more people from tuberculosis infection.

Incidence of pulmonary tuberculosis under the regular COVID-19 epidemic prevention and control in China

Background

The COVID-19 pandemic has driven public health intervention strategies, including keeping social distance, wearing masks in crowded places, and having good health habits, to prevent the transmission of the novel coronavirus (SARS-CoV-2). However, it is unknown whether the use of these intervention strategies influences morbidity in other human infectious diseases, such as tuberculosis.

Methods

In this study, three prediction models were constructed to compare variations in PTB incidences after January 2020 without or with intervention includes strict and regular interventions, when the COVID-19 outbreak began in China. The non-interventional model was developed with an autoregressive integrated moving average (ARIMA) model that was trained with the monthly incidence of PTB in China from January 2005 to December 2019. The interventional model was established using an ARIMA model with a continuing intervention function that was trained with the monthly PTB incidence in China from January 2020 to December 2020.

Results

Starting with the assumption that no COVID-19 outbreak had occurred in China, PTB incidence was predicted, and then the actual incidence was compared with the predicted incidence. A remarkable overall decline in PTB incidence from January 2020 to December 2020 was observed, which was likely due to the potential influence of intervention policies for COVID-19. If the same intervention strategy is applied for the next 2 years, the monthly PTB incidence would reduce on average by about 1.03 per 100,000 people each month compared with the incidence predicted by the non-interventional model. The annual incidence estimated 59.15 under regular intervention per 100,000 in 2021, and the value would decline to 50.65 with strict interventions.

Conclusions

Our models quantified the potential knock-on effect on PTB incidence of the intervention strategy used to control the transmission of COVID-19 in China. Combined with the feasibility of the strategies, these results suggested that continuous regular interventions would play important roles in the future prevention and control of PTB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07620-y.

The Potential Role of Vitamin D in the Development of Tuberculosis in Chinese Han Population: One Case-Control Study

Background and aims:

Spinal serum 25-hydroxyvitamin D [25[OH]D] status plays an important role in mediating innate immune responses by acting as a cofactor for induction of antimycobacterial activity and is thus involved in the development of Tuberculosis (TB). Results reported regarding the association of vitamin D with TB remained controversial. We aimed to identify any common association between 25[OH]D status and TB in the Chinese Han population.

Methods

280 subjects (70 TB patients and 210 matched controls) were recruited. TB cases were diagnosed based on the presence of acid-fast bacilli on smears from sputum and MTB isolation. Healthy controls were randomly selected from four local community-based populations. 25[OH]D was detected by electrochemiluminescence immunoassay (ECLIA) on Roche Elecsys before the initial treatment. Multivariable logistic regression analysis was used to examine the association of Vitamin D with TB.

Results

There was no significant difference in the serum vitamin D level between total cases and controls, but we found a strong tendency toward a higher serum vitamin D level in male population (P &lt; 0.05) with TB but not in females. High serum vitamin D increased the risk of TB in the Chinese Han population (OR = 1.035, 95%CI: 1.001–1.070, P &lt; 0.05). The serum vitamin D level was significantly decreased with age increasing in cases and controls (all P &lt; 0.001).

Conclusions

High serum vitamin D may be an independent risk factor for TB in the Chinese Han population.

Time trend prediction and spatial-temporal analysis of multidrug-resistant tuberculosis in Guizhou Province, China, during 2014-2020

Background

Guizhou is located in the southwest of China with high multidrug-resistant tuberculosis (MDR-TB) epidemic. To fight this disease, Guizhou provincial authorities have made efforts to establish MDR-TB service system and perform the strategies for active case finding since 2014. The expanded case finding starting from 2019 and COVID-19 pandemic may affect the cases distribution. Thus, this study aims to analyze MDR-TB epidemic status from 2014 to 2020 for the first time in Guizhou in order to guide control strategies.

Methods

Data of notified MDR-TB cases were extracted from the National TB Surveillance System correspond to population information for each county of Guizhou from 2014 to 2020. The percentage change was calculated to quantify the change of cases from 2014 to 2020. Time trend and seasonality of case series were analyzed by a seasonal autoregressive integrated moving average (SARIMA) model. Spatial–temporal distribution at county-level was explored by spatial autocorrelation analysis and spatial–temporal scan statistic.

Results

Guizhou has 9 prefectures and 88 counties. In this study, 1,666 notified MDR-TB cases were included from 2014–2020. The number of cases increased yearly. Between 2014 and 2019, the percentage increase ranged from 6.7 to 21.0%. From 2019 to 2020, the percentage increase was 62.1%. The seasonal trend illustrated that most cases were observed during the autumn with the trough in February. Only in 2020, a peak admission was observed in June. This may be caused by COVID-19 pandemic restrictions being lifted until May 2020. The spatial–temporal heterogeneity revealed that over the years, most MDR-TB cases stably aggregated over four prefectures in the northwest, covering Bijie, Guiyang, Liupanshui and Zunyi. Three prefectures (Anshun, Tongren and Qiandongnan) only exhibited case clusters in 2020.

Conclusion

This study identified the upward trend with seasonality and spatial−temporal clusters of MDR-TB cases in Guizhou from 2014 to 2020. The fast rising of cases and different distribution from the past in 2020 were affected by the expanded case finding from 2019 and COVID-19. The results suggest that control efforts should target at high-risk periods and areas by prioritizing resources allocation to increase cases detection capacity and better access to treatment.

Evaluating Strategies For Tuberculosis to Achieve the Goals of WHO in China: A Seasonal Age-Structured Model Study

Although great progress has been made in the prevention and mitigation of TB in the past 20 years, China is still the third largest contributor to the global burden of new TB cases, accounting for 833,000 new cases in 2019. Improved mitigation strategies, such as vaccines, diagnostics, and treatment, are needed to meet goals of WHO. Given the huge variability in the prevalence of TB across age-groups in China, the vaccination, diagnostic techniques, and treatment for different age-groups may have different effects. Moreover, the statistics data of TB cases show significant seasonal fluctuations in China. In view of the above facts, we propose a non-autonomous differential equation model with age structure and seasonal transmission rate. We derive the basic reproduction number, [Formula: see text], and prove that the unique disease-free periodic solution, [Formula: see text] is globally asymptotically stable when [Formula: see text], while the disease is uniformly persistent and at least one positive periodic solution exists when [Formula: see text]. We estimate that the basic reproduction number [Formula: see text] ([Formula: see text]), which means that TB is uniformly persistent. Our results demonstrate that vaccinating susceptible individuals whose ages are over 65 and between 20 and 24 is much more effective in reducing the prevalence of TB, and each of the improved vaccination strategy, diagnostic strategy, and treatment strategy leads to substantial reductions in the prevalence of TB per 100,000 individuals compared with current approaches, and the combination of the three strategies is more effective. Scenario A (i.e., coverage rate [Formula: see text], diagnosis rate [Formula: see text], relapse rate [Formula: see text]) is the best and can reduce the prevalence of TB per 100,000 individuals by [Formula: see text] and [Formula: see text] in 2035 and 2050, respectively. Although the improved strategies will significantly reduce the incidence rate of TB, it is challenging to achieve the goal of WHO in 2050. Our findings can provide guidance for public health authorities in projecting effective mitigation strategies of TB.

Social Support and Depression Among Pulmonary Tuberculosis Patients in Anhui, China

Introduction

Pulmonary tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis affecting multiple tissues and organs. It is one of the leading causes of death and is a social disease in China. Increasing studies have revealed that the state of mental health and the social support are associated with the morbidity, mortality and community transmission of pulmonary TB patients. However, the previous global TB control and research strategy focused almost solely on the biomedical aspects. Therefore, in this study, we evaluated the level of depression and explored potential factors, including social support domains and socio-demographic characteristics in pulmonary TB patients to research the mental health state and the association between social support and pulmonary TB, ultimately implementing a multilevel intervene.

Methods

A cross-sectional study was carried out to describe the status of depression and social support, and explore related factors associated with depression among pulmonary TB patients in Anhui Province, China. Five counties (districts) in Anhui Province, China were selected by simple random sampling method. Patients diagnosed with pulmonary TB eligible to the study criteria were investigated. A structured questionnaire composed of information on socio-demographic characteristics, self-rating depression scale (SDS) and social support rating scale (SSRS) was used to collect the data.

Results

In this study, a total of 250 questionnaires were issued, and the effective questionnaires 237 were actually returned. Of the 237 patients with pulmonary TB, 71.3% of them were male and the mean age was 46.16 years (SD = 13.09). Depression symptoms were observed in 125 (52.7%) participants. Objective support (β = −0.192, P=0.002) and subjective support (β = −0.158, P = 0.015) had significantly negative effects on depression, while the effect of support utilization was not statistically significant. In contrast, being female (β = 0.119, P = 0.036) and patients with positive sputum smear results (β = 0.140, P = 0.014) were positively related to depression. Patients with monthly income between 500 and 999 were less likely to suffer from depression (β = −0.134, P = 0.024) than those who were poorer. Additionally, both education level and marital status were found to be correlated with social support and depression state (all P<0.05).

Discussion

In summary, the prevalence of depressive symptoms in pulmonary TB patients were high in Anhui Province, China. Low levels of social support can be an important predictor of depression symptoms. Therefore, screening for depression among pulmonary TB patients in the primary care setting is greatly warranted. Furthermore, psychological interventions should focus on providing available and adequate social support in order to improve mental health of them.

Impact of the gate-keeping policies of China's primary healthcare model on the future burden of tuberculosis in China: a protocol for a mathematical modelling study

INTRODUCTION

In the past three decades, China has made great strides in the prevention and treatment of tuberculosis (TB). However, the TB burden remains high. In 2019, China accounted for 8.4% of global incident cases of TB, the third highest in the world, with a higher prevalence in rural areas. The Healthy China 2030 highlights the gate-keeping role of primary healthcare (PHC). However, the impact of PHC reforms on the future TB burden is unclear. We propose to use mathematical models to project and evaluate the impacts of different gate-keeping policies.

METHODS AND ANALYSIS

We will develop a deterministic, population-level, compartmental model to capture the dynamics of TB transmission within adult rural population. The model will incorporate seven main TB statuses, and each compartment will be subdivided by service providers. The parameters involving preference for healthcare seeking will be collected using discrete choice experiment (DCE) method. We will solve the deterministic model numerically over a 20-year (2021-2040) timeframe and predict the TB prevalence, incidence and cumulative new infections under the status quo or various policy scenarios. We will also conduct an analysis following standard protocols to calculate the average cost-effectiveness for each policy scenario relative to the status quo. A numerical calibration analysis against the available published TB prevalence data will be performed using a Bayesian approach.

ETHICS AND DISSEMINATION

Most of the data or parameters in the model will be obtained based on secondary data (eg, published literature and an open-access data set). The DCE survey has been reviewed and approved by the Ethics Committee of the School of Public Health, Sun Yat-sen University. The approval number is SYSU [2019]140. Results of the study will be disseminated through peer-reviewed journals, media and conference presentations.

The epidemiologic impact and cost-effectiveness of new tuberculosis vaccines on multidrug-resistant tuberculosis in India and China

BACKGROUND

Despite recent advances through the development pipeline, how novel tuberculosis (TB) vaccines might affect rifampicin-resistant and multidrug-resistant tuberculosis (RR/MDR-TB) is unknown. We investigated the epidemiologic impact, cost-effectiveness, and budget impact of hypothetical novel prophylactic prevention of disease TB vaccines on RR/MDR-TB in China and India.

METHODS

We constructed a deterministic, compartmental, age-, drug-resistance- and treatment history-stratified dynamic transmission model of tuberculosis. We introduced novel vaccines from 2027, with post- (PSI) or both pre- and post-infection (P&PI) efficacy, conferring 10 years of protection, with 50% efficacy. We measured vaccine cost-effectiveness over 2027-2050 as USD/DALY averted-against 1-times GDP/capita, and two healthcare opportunity cost-based (HCOC), thresholds. We carried out scenario analyses.

RESULTS

By 2050, the P&PI vaccine reduced RR/MDR-TB incidence rate by 71% (UI: 69-72) and 72% (UI: 70-74), and the PSI vaccine by 31% (UI: 30-32) and 44% (UI: 42-47) in China and India, respectively. In India, we found both USD 10 P&PI and PSI vaccines cost-effective at the 1-times GDP and upper HCOC thresholds and P&PI vaccines cost-effective at the lower HCOC threshold. In China, both vaccines were cost-effective at the 1-times GDP threshold. P&PI vaccine remained cost-effective at the lower HCOC threshold with 49% probability and PSI vaccines at the upper HCOC threshold with 21% probability. The P&PI vaccine was predicted to avert 0.9 million (UI: 0.8-1.1) and 1.1 million (UI: 0.9-1.4) second-line therapy regimens in China and India between 2027 and 2050, respectively.

CONCLUSIONS

Novel TB vaccination is likely to substantially reduce the future burden of RR/MDR-TB, while averting the need for second-line therapy. Vaccination may be cost-effective depending on vaccine characteristics and setting.

Assessing the Quality of Reporting to China's National TB Surveillance Systems

(1) Background: The reliability of disease surveillance may be restricted by sensitivity or ability to capture all disease. Objective: To quantify under-reporting and concordance of recording persons with tuberculosis (TB) in national TB surveillance systems: the Infectious Disease Reporting System (IDRS) and Tuberculosis Information Management System (TBIMS). (2) Methods: This retrospective review includes 4698 patients identified in 2016 in China. County staff linked TB patients identified from facility-specific health and laboratory information systems with records in IDRS and TBIMS. Under-reporting was calculated, and timeliness, concordance, accuracy, and completeness were analyzed. Multivariable logistic regression was used to examine factors associated with under-reporting. (3) Results: We found that 505 (10.7%) patients were missing within IDRS and 1451 (30.9%) patients were missing within TBIMS. Of 171 patient records reviewed in IDRS and 170 patient records in TBIMS, 12.3% and 6.5% were found to be untimely, and 10.7% and 7.1% were found to have an inconsistent home address. The risk of under-reporting to both IDRS and TBIMS was greatest at tertiary health facilities and among non-residents; the risk of under-reporting to TBIMS was greatest with patients aged 65 or older and with extrapulmonary TB (EPTB). (4) Conclusions: It is important to improve the reporting and recording of TB patients. Local TB programs that focus on training, and mentoring high-burden hospitals, facilities that cater to EPTB, and migrant patients may improve reporting and recording.

Assessment of Strategies and Epidemiological Characteristics of Tuberculosis in Henan Province, China: Observational Study

Background

In 2005, China established an internet-based Tuberculosis Information Management System (TBIMS) to monitor changes in tuberculosis (TB). Many scholars have conducted epidemiological research using TBIMS; however, few studies assessing control strategies have been performed based on this platform data. Henan province is a high TB incidence area in China where, in addition to following the nationwide TB strategies, a series of local intervention combinations have been implemented.

Objective

Our study aims to evaluate the impact of nationwide TB intervention combinations on epidemiological changes and determine whether Henan province can achieve the World Health Organization’s (WHO) goal of reducing TB incidence by 50% and TB mortality by 75% by the year 2025.

Methods

We used descriptive statistical methods to show the spatial and temporal distribution of pulmonary tuberculosis (PTB) reported to the TBIMS database from 2005 to 2018, and logistic regression analysis was performed to identify the risk factors of bacteriological-positive TB. The dynamic compartmental model and Bayesian melding approach was adopted to estimate the burden of TB under the impact of different TB control policies.

Results

In total, 976,526 PTB cases were notified to the TBIMS in Henan in a period of 14 years. Although the overall incidence of PTB declined from 91.4/10⁵ to 58.5/10⁵, and the overall incidence of bacteriological-positive PTB declined from 44.5/10⁵ to 14.7/10⁵, the WHO’s 2025 goal could not be met. The distribution of high incidence and poverty-stricken counties were basically overlapped. Men, farmers and herdsmen (in rural areas), and subjects aged ≥60 years were more likely to develop bacteriological-positive PTB. The increasing treatment success for drug-susceptible tuberculosis and multidrug-resistant tuberculosis has not provided the desired reduction in incidence and mortality.

Conclusions

To achieve the targeted goal, while improving the cure rate of TB, new active (rather than passive) detection and intervention strategies should be formulated based on epidemiological characteristics in Henan province.

Potential impact of tuberculosis vaccines in China, South Africa, and India

More effective tuberculosis vaccines are needed to help reach World Health Organization tuberculosis elimination goals. Insufficient evidence exists on the potential impact of future tuberculosis vaccines with varying characteristics and in different epidemiological settings. To inform vaccine development decision making, we modeled the impact of hypothetical tuberculosis vaccines in three high-burden countries. We calibrated Mycobacterium tuberculosis (M.tb) transmission models to age-stratified demographic and epidemiological data from China, South Africa, and India. We varied vaccine efficacy to prevent infection or disease, effective in persons M.tb uninfected or infected, and duration of protection. We modeled routine early-adolescent vaccination and 10-yearly mass campaigns from 2025. We estimated median percentage population-level tuberculosis incidence rate reduction (IRR) in 2050 compared to a no new vaccine scenario. In all settings, results suggested vaccines preventing disease in M.tb-infected populations would have greatest impact by 2050 (10-year, 70% efficacy against disease, IRR 51%, 52%, and 54% in China, South Africa, and India, respectively). Vaccines preventing reinfection delivered lower potential impact (IRR 1, 12, and 17%). Intermediate impact was predicted for vaccines effective only in uninfected populations, if preventing infection (IRR 21, 37, and 50%) or disease (IRR 19, 36, and 51%), with greater impact in higher-transmission settings. Tuberculosis vaccines have the potential to deliver substantial population-level impact. For prioritizing impact by 2050, vaccine development should focus on preventing disease in M.tb-infected populations. Preventing infection or disease in uninfected populations may be useful in higher transmission settings. As vaccine impact depended on epidemiology, different development strategies may be required.

Epidemic Trends of Tuberculosis in China from 1990 to 2017: Evidence from the Global Burden of Disease Study

PURPOSE

Tuberculosis remains a major public health problem globally, especially in undeveloped countries. This study aimed to evaluate and review the long-term epidemic trends of tuberculosis in China.

METHODS

Data were extracted from the Global Health Data Exchange. Metrics (prevalence, incidence and mortality) and Joinpoint regression were used to identify the epidemic trends.

RESULTS

From 1990 to 2017, decreasing trends in prevalence (average annual percent change, AAPC: -0.5%, 95% CI: -0.6% to -0.5%), incidence (-3.2%, 95% CI: -3.5% to -2.9%), and mortality (-5.7%, 95% CI: -6.2% to -5.3%) of tuberculosis were observed. The incidence and mortality of multidrug-resistant tuberculosis (MDR-TB) decreased with AAPC of -2.3% (-3.1% to -1.4%) and -4.9% (-5.4% to -4.5%), respectively, while the prevalence increased with an AAPC of 1.2% (0.3% to 2.0%). The burden of extensively drug-resistant tuberculosis (XDR-TB) increased with an AAPC of 12.5% (11.9% to 13.2%) in prevalence, 7.6% (6.5% to 8.7%) in incidence, and 4.5% (3.6% to 5.4%) in mortality. The disease burden of tuberculosis increased with age and peaked among those aged over 70.

CONCLUSION

The epidemic of tuberculosis decreased in China, while the disease burden was still challenging to control. MDR-TB and XDR-TB should be emphasized along with the epidemic. It will certainly be a difficult task to achieve the post-2015 global targets by 2025 and 2035.

Rising challenge of multidrug-resistant tuberculosis in China: a predictive study using Markov modeling

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is on the rise in China. This study used a dynamic Markov model to predict the longitudinal trends of MDR-TB in China by 2050 and to assess the effects of alternative control measures.

METHODS

Eight states of tuberculosis transmission were set up in the Markov model using a hypothetical cohort of 100 000 people. The prevalence of MDR-TB and bacteriologically confirmed drug-susceptible tuberculosis (DS-TB+) were simulated and MDR-TB was stratified into whether the disease was treated with the recommended regimen or not.

RESULTS

Without any intervention changes to current conditions, the prevalence of DS-TB+ was projected to decline 67.7% by 2050, decreasing to 20 per 100 000 people, whereas that of MDR-TB was expected to triple to 58/100 000. Furthermore, 86.2% of the MDR-TB cases would be left untreated by the year of 2050. In the case where MDR-TB detection rate reaches 50% or 70% at 5% per year, the decline in prevalence of MDR-TB would be 25.9 and 36.2% respectively. In the case where treatment coverage was improved to 70% or 100% at 5% per year, MDR-TB prevalence in 2050 would decrease by 13.8 and 24.1%, respectively. If both detection rate and treatment coverage reach 70%, the prevalence of MDR-TB by 2050 would be reduced to 28/100 000 by a 51.7% reduction.

CONCLUSIONS

MDR-TB, especially untreated MDR-TB, would rise rapidly under China's current MDR-TB control strategies. Interventions designed to promote effective detection and treatment of MDR-TB are imperative in the fights against MDR-TB epidemics.

Safety and treatment completion of latent tuberculosis infection treatment in the elderly population-A prospective observational study in Taiwan

BACKGROUND

The detection and treatment of latent tuberculosis infection (LTBI) is a key step in eliminating tuberculosis (TB), but information on safety and on treatment interruption in elderly LTBI patients remains limited.

METHODS

This multicenter prospective observational study included individuals with LTBI who underwent preventive therapy. Incidents of systemic adverse reactions (SARs) and treatment interruption rates in an elderly group (≥60 years old) and a young group (<60 years old) were analyzed.

RESULTS

A total of 406 LTBI patients, comprising 167 elderly and 239 young patients, were included in the analyses. The incidence of SARs was similar in the elderly group (18%) and the young group (15.1%). Being middle-aged (35-59 years), body mass index <23 kg/m², a regimen of 3 months of once-weekly rifapentine plus isoniazid, and end-stage renal disease were independent factors associated with SARs. The treatment interruption rate was similar between the elderly group (21.6%) and the young group (15.9%). LTBI patients aged ≥80 years with SARs had the highest risk of treatment interruption.

CONCLUSIONS

The occurrence of SARs was similar in the elderly (≥60 years old) and young (<60 years old) LTBI patients receiving preventive therapy. Extremely old (≥80 years old) LTBI patients had a higher treatment interruption rate, especially when they had SARs.

Utilization and expenses of outpatient services among tuberculosis patients in three Chinese counties: an observational comparison study

Background

The China-Gates TB project Phase II implemented case-based payment reform in three Chinese counties in 2014, designed specifically for patients diagnosed with Tuberculosis (TB). This study aimed to examine the changes in utilization and expenses of outpatient services before and after the reform implementation, among TB patients in the three counties in China.

Methods

We collected quantitative data using surveys in 2013 (baseline year) and 2015 (final year). We used outpatient hospital records to measure service utilization and medical expenses of TB patients. We conducted qualitative interviews with local health authorities, officers of health insurance agencies, and hospital managers (n = 18). We utilized three focus group discussions with hospital staff and TB doctors and nurses. The χ² tests and Mann-Whitney U tests were used to analyse quantitative data, and the thematic analysis using a framework approach was applied to analyse qualitative data.

Results

Dantu and Yangzhong counties enacted TB-specific case-based payment method in 2014. Jurong County maintained global budget payment but raised the reimbursement rate for TB care. Compared to the baseline, the percentage of TB patients in Dantu and Yangzhong with eight or above outpatient visits increased from 7.5 to 55.1% and from 22.1 to 53.1% in the final survey, respectively. Jurong experienced the opposite trend, decreasing from 63.0 to 9.8%. In the final survey, the total outpatient expenses per patient during a full treatment course in Dantu (RMB 2939.7) and Yangzhong (RMB 2520.6) were significantly higher than those in the baseline (RMB 690.4 and RMB 1001.5, respectively), while the total outpatient expenses in Jurong decreased significantly (RMB 1976.0 in the baseline and RMB 660.8 in the final survey). Health insurance agencies in Dantu and Yangzhong did not approve the original design with outpatient and inpatient expenses packaged together, revealed by qualitative interviews. Furthermore, staff at designated hospitals misunderstood that health insurance agencies would only reimburse actual expenses. Many TB doctors complained about their reduced salary, which might be due to decreased hospital revenue generated from TB care after the payment method reform.

Conclusions

The intended effect on cost containment of case-based payment was not evident in Dantu and Yangzhong. In Jurong, where the global budget payment system maintained with the reimbursement rate enhanced, we found an effect on cost containment, but the quality of TB care might be compromised. The TB-specific case-based payment method could be redesigned to combine payment on outpatient and inpatient expenses and to set an appropriate payment standard for TB care during a full treatment course. Local health insurance agencies have to provide explicit explanations on the payment method. TB care providers should be provided with proper incentives. Monitoring and evluaiton on the quality of TB care should be undertaken at regular intervals.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0590-0) contains supplementary material, which is available to authorized users.

Population-level mathematical modeling of antimicrobial resistance: a systematic review

BACKGROUND

Mathematical transmission models are increasingly used to guide public health interventions for infectious diseases, particularly in the context of emerging pathogens; however, the contribution of modeling to the growing issue of antimicrobial resistance (AMR) remains unclear. Here, we systematically evaluate publications on population-level transmission models of AMR over a recent period (2006-2016) to gauge the state of research and identify gaps warranting further work.

METHODS

We performed a systematic literature search of relevant databases to identify transmission studies of AMR in viral, bacterial, and parasitic disease systems. We analyzed the temporal, geographic, and subject matter trends, described the predominant medical and behavioral interventions studied, and identified central findings relating to key pathogens.

RESULTS

We identified 273 modeling studies; the majority of which (> 70%) focused on 5 infectious diseases (human immunodeficiency virus (HIV), influenza virus, Plasmodium falciparum (malaria), Mycobacterium tuberculosis (TB), and methicillin-resistant Staphylococcus aureus (MRSA)). AMR studies of influenza and nosocomial pathogens were mainly set in industrialized nations, while HIV, TB, and malaria studies were heavily skewed towards developing countries. The majority of articles focused on AMR exclusively in humans (89%), either in community (58%) or healthcare (27%) settings. Model systems were largely compartmental (76%) and deterministic (66%). Only 43% of models were calibrated against epidemiological data, and few were validated against out-of-sample datasets (14%). The interventions considered were primarily the impact of different drug regimens, hygiene and infection control measures, screening, and diagnostics, while few studies addressed de novo resistance, vaccination strategies, economic, or behavioral changes to reduce antibiotic use in humans and animals.

CONCLUSIONS

The AMR modeling literature concentrates on disease systems where resistance has been long-established, while few studies pro-actively address recent rise in resistance in new pathogens or explore upstream strategies to reduce overall antibiotic consumption. Notable gaps include research on emerging resistance in Enterobacteriaceae and Neisseria gonorrhoeae; AMR transmission at the animal-human interface, particularly in agricultural and veterinary settings; transmission between hospitals and the community; the role of environmental factors in AMR transmission; and the potential of vaccines to combat AMR.

Prognostic value of serum macrophage migration inhibitory factor levels in pulmonary tuberculosis

Background

Macrophage migration inhibitory factor (MIF) makes chemokine-like functions and plays critical roles in various inflammatory diseases. This study was designed to explore the significance of MIF serum levels in predicting the prognosis of pulmonary tuberculosis (PTB) following anti-TB treatment.

Methods

Patients diagnosed with culture-confirmed PTB without treatment were included and the serum was collected. Levels of MIF in serum were quantified with immunoassay, and the levels of established biomarkers were also determined, including C-reactive protein (CRP) and Interleukin 6 (IL-6). The outcome was estimated with all-cause mortality, with the mortality in 12 months as the primary outcome and the mortality in 3, 6, 9 months as other outcomes. The prognostic value of MIF and other factors in PTB were tested.

Results

Two hundred eighty-seven PTB patients were included. The median MIF levels in patients with advanced disease, disseminated and drug-resistant TB were significantly higher than that observed in mild -to- moderate disease, non-disseminated and drug-sensitive TB. MIF levels in patients with the outcome of death were higher than those survived [28.0 ng/ml (Inter-quartile range [IQR]: 24.2–33.1) vs. 22.3 ng/ml (IQR: 18.7–26.5); P < 0.001]. Multivariate model analysis was performed for comparing the highest quartiles to the lowest quartile of MIF levels. MIF levels were related to the mortality, with an elevated mortality risk of 236% [Odds ratio (OR) = 3.36; 95% Confidence interval (CI): 1.21–15.14; P = 0.012]. The model was re-analysis after combing MIF with currently established risk indicators. The obtained Area Under the Receiver Operating Characteristic Curve (±standard error) was elevated from 0.81 (±0.035) to 0.84 (±0.031), with a significant difference before and after adding the MIF (difference, 0.03[0.004]; P = 0.03).

Conclusion

Serum level of MIF was a better biomarker than CRP or IL-6 for predicting death in HIV-negative PTB patients, and increased MIF serum levels were related to higher mortality.

Age-targeted tuberculosis vaccination in China and implications for vaccine development: a modelling study

BACKGROUND

Tuberculosis is the leading single-pathogen cause of death worldwide, and China has the third largest number of cases worldwide. New tools, such as new vaccines, are needed to meet WHO tuberculosis goals. Tuberculosis vaccine development strategies mostly target infants or adolescents, but given China's ageing epidemic, vaccinating older people might be important. We modelled the potential impact of new tuberculosis vaccines in China targeting adolescents (15-19 years) or older adults (60-64 years) with varying vaccine characteristics to inform strategic vaccine development.

METHODS

A Mycobacterium tuberculosis transmission model was calibrated to age-stratified demographic and epidemiological data from China. Varying scenarios of vaccine implementation (age targeting [adolescents or older adults] and coverage [30% or 70%]) and characteristics (efficacy [40%, 60%, or 80%], duration of protection [10 years or 20 years], and host infection status required for efficacy [pre-infection, post-infection in latency, post-infection in latency or recovered, or pre-infection and post-infection]) were assessed. Primary outcomes were tuberculosis incidence and mortality rate reduction in 2050 in each vaccine scenario compared with the baseline (no new vaccine) scenario and cumulative number needed to vaccinate (NNV) per case or death averted, 2025-50.

FINDINGS

By 2050, results suggest that 74·5% (uncertainty interval [UI] 70·2-78·6) of incident tuberculosis cases in China would occur in people aged 65 years or older, and 75·1% (66·8-80·7) of all cases would be due to reactivation, rather than new infection. All vaccine profiles delivered to older adults had higher population-level impact (reduction of incidence and mortality rates) and lower NNV per case and per death averted than if delivered to adolescents. For an intermediate vaccine scenario of 60% efficacy, 10-year protection, and 70% coverage, the reduction of tuberculosis incidence rates with older adult vaccination was 1·9 times (UI 1·5-2·6) to 157·5 times (119·3-225·6) greater than with adolescent vaccination, and the NNV was 0·011 times (0·008-0·014) to 0·796 times (0·632-0·970) lower. Furthermore, with older adult vaccination, post-infection vaccines provided substantially greater mortality and incidence rate reductions than pre-infection vaccines.

INTERPRETATION

Adolescent-targeted tuberculosis vaccines, the focus of many development plans, would have only a small impact in ageing, reactivation-driven epidemics such as those in China. Instead, an efficacious post-infection vaccine delivered to older adults will be crucial to maximise population-level impact in this setting and would provide an important contribution towards achieving WHO goals. Older adults should be included in tuberculosis vaccine clinical development and implementation planning.

FUNDING

Aeras and UK MRC.

Trend in risk of delay in diagnosis of new pulmonary tuberculosis in Northwest China from 2008 to 2017

Background

With great changes over the past 10 years in China, especially the rapid economic development, population mobility, urbanization and aging, dynamic change on risk of delay, to our knowledge, has not been well studied in China. The study was to explore risk of delay in diagnosis of new pulmonary tuberculosis (PTB) and dynamic changes in risk of delay in Northwest China.

Methods

From January 1, 2008 to December 31, 2017, a total of 13,603 people with new PTB registered in Yulin city of Shaanxi province were included. The median delay time was estimated by Kaplan-Meier survival curve. Time delay curves of year-, gender-year-, age-year- and smear-year specific were examined using log-rank test. Two-level mixed-effects survival model was used to calculate the hazard ratio (HR) and 95% confidence interval (95%CI) for factors associated with diagnostic delay. Time delay was defined as time interval between the onset of PTB symptoms and being diagnosed. The outcome variable of interest was defined as “being diagnosed” in survival analysis.

Results

The 10-year delay time was 33 days (Interquartile Range, 16–65). Annual median delay time gradually decreased from 60 days to 33 days during the past 10 years. The probability that individuals were diagnosed since onset of PTB symptoms increased by 1.29 times in 2017 when compared to 2008. Female (Hazard Ratio (HR), 95%CI, 0.95(0.91–0.99)), age>45 years (HR, 95%CI, 0.87(0.82–0.93)) and smear positive (HR, 95%CI, 0.86(0.78–0.95)) were associated with increased risk of diagnostic delay over 10-year timespan. However, Age>45 years and smear positive showed trend to be protective factors in the past 5 years.

Conclusions

Time and risk of delay in diagnosis of new PTB had declined over the past 10 years. However, more attentions should be paid to the fact that female still suffered from higher risk of diagnostic delay. We noted a potential reversal in traditional risk factors such as age>45 and smear positive. Those dynamic changes deserved further attention.

Under-reporting of diagnosed tuberculosis to the national surveillance system in China: an inventory study in nine counties in 2015

OBJECTIVE

The WHO estimates that almost 40% of patients diagnosed with tuberculosis (TB) are not reported. We implemented this study to assess TB under-reporting and delayed treatment registration in nine counties in China.

DESIGN

A retrospective inventory study (record review).

SETTING

Counties were selected using purposive sampling from nine provinces distributed across eastern, central and western regions of China in 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

Under-reporting was calculated as the percentage of patients with TB not reported to TB Information Management System (TBIMS) within 6 months of diagnosis. Delayed registration was estimated as the percentage of reported cases initiating treatment 7 or more days after diagnosis. Multivariable logistic regression and an alpha level of 0.05 were used to examine factors associated with these outcomes.

RESULTS

Of the 5606 patients with TB identified from project health facilities and social insurance systems, 1082 (19.3%) were not reported to TBIMS. Of the 4524 patients successfully reported, 1416 (31.3%) were not registered for treatment within 7 days of diagnosis. Children, TB pleurisy, patients diagnosed in the eastern and central regions and patients with a TB diagnosis recorded in either health facilities or social insurance system-but not both-were statistically more likely to be unreported. Delayed treatment registration was more likely for previously treated patients with TB, patients with negative or unknown sputum results and for patients diagnosed in the eastern region.

CONCLUSION

Almost one in every five patients diagnosed with TB in this study was unknown to local or national TB control programmes. We recommend strengthening TB data management practices, particularly in the eastern and central regions, and developing specific guidelines for reporting paediatric TB and TB pleurisy. Patient education and follow-up by diagnosing facilities could improve timely treatment registration. Additional studies are needed to assess under-reporting elsewhere in China.

Short-course regimens of rifapentine plus isoniazid to treat latent tuberculosis infection in older Chinese patients: a randomised controlled study

Latent tuberculosis infection (LTBI) management is now a critical component of the World Health Organization's End TB Strategy.In this randomised controlled trial (Chinese Clinical Trial Registry identifier ChiCTR-IOR-15007202), two short-course regimens with rifapentine plus isoniazid (a 3-month once-weekly regimen and a 2-month twice-weekly regimen) were initially designed to be evaluated for rural residents aged 50-69 years with LTBI in China.Due to the increasingly rapid growth and unexpected high frequency of adverse effects, the treatments were terminated early (after 8 weeks for the once-weekly regimen and after 6 weeks for the twice-weekly regimen). In the modified intention-to-treat analysis on the completed doses, the cumulative rate of active disease during 2 years of follow-up was 1.21% (14 out of 1155) in the untreated controls, 0.78% (10 out of 1284) in the group that received the 8-week once-weekly regimen and 0.46% (six out of 1299) in the group that received the 6-week twice-weekly regimen. The risk of active disease was decreased, with an adjusted hazard ratio of 0.63 (95% CI 0.27-1.43) and 0.41 (95% CI 0.15-1.09) for the treatments, respectively. No significant difference was found in the occurrence of hepatotoxicity (1.02% (13 out of 1279) versus 1.17% (15 out of 1279); p=0.704).The short regimens tested must be used with caution among the elderly because of the high rates of adverse effects. Further work is necessary to test the ultrashort regimens in younger people with LTBI.

Surgical release for tubercular elbow stiffness

Background

For decades, tuberculosis (TB) has posed a great threat to people worldwide. Bone and joint TB is one of the most common types of extrapulmonary TB, with elbow TB comprising a small proportion of these cases. The treatment for elbow stiffness associated with TB has been rarely reported.

Patients and methods

We retrospectively analyzed six patients (four females and two males) with tubercular elbow stiffness during a 7-year period. All of them received open arthrolysis and hinged external fixation to restore functional extension, flexion, supination and pronation. Mayo Elbow Performance Score (MEPS) and range of motion (ROM) were evaluated preoperatively and at final follow-up.

Results

At final follow-up after surgery, we evaluated the average active ROM, which was 111.7° (90°–135°). The average extension was 11.7° (0°–30°), while the average flexion was 123.3° (115°–135°). At the same time, the average supination was increased to 70° (40°–90°) and the average pronation was increased to 68.3° (45°–80°). The MEPS was elevated to 92.5 (85–100). Three patients displayed complications and were treated and cured with dressing changes and antibiotics.

Conclusion

Open arthrolysis and hinged external fixation are useful for the treatment of non-traumatic elbow stiffness with TB.

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology for tuberculosis control

Tuberculosis (TB) has remained an ongoing concern in China. The national scale-up of the Directly Observed Treatment, Short Course (DOTS) program has accelerated the fight against TB in China. Nevertheless, many challenges still remain, including the spread of drug-resistant strains, high disease burden in rural areas, and enormous rural-to-urban migrations. Whether incident active TB represents recent transmission or endogenous reactivation has helped to prioritize the strategies for TB control. Evidence from molecular epidemiology studies has delineated the recent transmission of Mycobacterium tuberculosis (M. tuberculosis) strains in many settings. However, the transmission patterns of TB in most areas of China are still not clear. Studies carried out to date could not capture the real burden of recent transmission of the disease in China because of the retrospective study design, incomplete sampling, and use of low-resolution genotyping methods. We reviewed the implementations of molecular epidemiology of TB in China, the estimated disease burden due to recent transmission of M. tuberculosis strains, the primary transmission of drug-resistant TB, and the evaluation of a feasible genotyping method of M. tuberculosis strains in circulation.

Tuberculosis infection in rural labor migrants in Shenzhen, China: Emerging challenge to tuberculosis control during urbanization

During China’s urbanization process, rural labor migrants have been suggested to be one important bridge population to change urban-rural distribution on tuberculosis (TB) burden. Aiming to estimate the prevalence of TB infection and to track the active disease development in rural labor migrants, a prospective study was conducted in Shenzhen city, southern China. TB infection was detected using interferon-γ release assay (IGRA). Here we mainly report the characteristics of TB infection in the study population based on the baseline survey. A total of 4,422 eligible participants completed baseline survey in July 2013. QuantiFERON (QFT) positivity rates 17.87% (790/4,422) and was found to be consistent with the local TB epidemic of the areas where the participants immigrated from. Age, smoking, residence registered place, and present of BCG scars were found to be independently associated with QFT positivity. Additionally, evidence for interaction between smoking and age was observed (p for likelihood ratio test < 0.001). Our results suggested that the development of TB control strategy including latent TB infection management should pay more attention to the rural flowing population due to their high mobility and higher prevalence of TB infection.

Tuberculosis in China: A longitudinal predictive model of the general population and recommendations for achieving WHO goals

BACKGROUND AND OBJECTIVE

Tuberculosis (TB) remains a major public health challenge. China accounts for more than 10% of the global TB burden, and effective modelling of TB trends remains limited.

METHODS

We used data drawn primarily from two Chinese nation-wide cross-sectional epidemiological surveys combined with data from China's National Disease Reporting Network to construct an eight-state Markov model that simulates TB prevalence. By adjusting the relevant parameters, we evaluated which characteristics have the greatest bearing upon prevalence and efficacy of the response measures.

RESULTS

If current trends continue, the prevalence of TB in China will enter an 8-year period of decline from approximately 390 to 200 cases per 100 000 population and stabilize at 163 cases per 100 000 population, which is a figure well above the World Health Organization (WHO) goal of eliminating TB by 2050. We find that the proportion of notified cases in the population, the rate of progression from latent to active and the overall treatment success rate are the chief factors affecting disease progression.

CONCLUSION

We suggest a 90-90-90 strategy, wherein the proportion of notified cases in the population reaches 90%, the risk of progression from latent to active is decreased by 90% compared with the current level and the overall treatment success rate is increased to 90%. This strategy could reduce TB prevalence to less than 10 cases per 100 000 population within 5 years and to 1.77 cases per 100 000 population within 50 years.

Distinct Prevalence of Drug-Resistant Tuberculosis in Gansu, China: A Retrospective Study on Drug Susceptibility Profiles Between 2010 and 2014

Limited knowledge is available on regional distribution of antituberculosis (TB) drug resistance and on province-specific time-trends in TB drug susceptibility in China. To obtain the latest information about the dynamics of drug-resistant TB in Gansu province, we conducted a retrospective study and analyzed data on drug resistance among new TB cases diagnosed between June 2010 and May 2014 in Gansu, China. The data were collected from the only TB surveillance and treatment hospital in Gansu and, therefore, represented the epidemiology of TB in the province. The drug resistance was defined based on diagnostic drug susceptibility testing. Overall, 17.3% of TB new cases diagnosed during 2010 to 2014 in Gansu presented resistance to at least one anti-TB drug. And a total of 2.9% of new TB cases have multidrug resistance. The prevalence of multidrug-resistant TB in Gansu was found to resurge after 2013 (2.0%) after a steady decline between 2010 and 2012 (from 7.1% to 1.2%). The drug resistance patterns of TB and their revolution trends in Gansu differed from other regions of China. We report the first epidemiological description of drug-resistant TB in Gansu, which is distinct when compared to other regions. Our data demonstrate that the distribution of drug-resistant TB varies to a great extent among different geographic regions. And the results of our study greatly suggest that the implementation of individualized TB management and regimen policy based on the regional epidemiology of TB drug susceptibility is highly required.

Patient characteristics and perceived health status of individuals with HIV and tuberculosis coinfection in Guangxi, China

To explore demographics, clinical and medication profiles, patients' social support, and perceived health status in HIV/TB coinfected patients in Guangxi, China.We performed a cross-sectional study in the HIV clinic of the Guigang City People's Hospital (N = 150). Health professionals conducted face-to-face interviews and collected data from patients' electronic medical records regarding patients' demographic, clinical, and medication information, as well as their social support and perceived health status. We classified all HIV/AIDS patients into HIV monoinfected and TB coinfected, at a ratio of 2:1.Compared with the HIV monoinfected, patients with HIV/TB coinfection were more likely to be older, male, less educated, unemployed, carrying health insurance, having advanced stage of HIV infection, longer history with HIV, and other opportunistic infections. Patients coinfected with TB were also more likely to hold a negative belief that their HIV treatment could prevent exacerbations, and reported significantly worse emotional/informational support, social interaction, and perceived health status. Better social support and better self-efficacy to the HIV treatment adherence was significantly associated with better perceived health status among patients with HIV and TB coinfection.Having HIV/TB coinfection was associated with poorer perceived general well-being and mental health, particularly in those undergoing TB therapy. Our findings suggest the need for mental health referrals and medication management for coinfected individuals, as well as further efforts and policies to improve coordinated care.

The epidemiology, pathogenesis, transmission, diagnosis, and management of multidrug-resistant, extensively drug-resistant, and incurable tuberculosis

Global tuberculosis incidence has declined marginally over the past decade, and tuberculosis remains out of control in several parts of the world including Africa and Asia. Although tuberculosis control has been effective in some regions of the world, these gains are threatened by the increasing burden of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. XDR tuberculosis has evolved in several tuberculosis-endemic countries to drug-incurable or programmatically incurable tuberculosis (totally drug-resistant tuberculosis). This poses several challenges similar to those encountered in the pre-chemotherapy era, including the inability to cure tuberculosis, high mortality, and the need for alternative methods to prevent disease transmission. This phenomenon mirrors the worldwide increase in antimicrobial resistance and the emergence of other MDR pathogens, such as malaria, HIV, and Gram-negative bacteria. MDR and XDR tuberculosis are associated with high morbidity and substantial mortality, are a threat to health-care workers, prohibitively expensive to treat, and are therefore a serious public health problem. In this Commission, we examine several aspects of drug-resistant tuberculosis. The traditional view that acquired resistance to antituberculous drugs is driven by poor compliance and programmatic failure is now being questioned, and several lines of evidence suggest that alternative mechanisms-including pharmacokinetic variability, induction of efflux pumps that transport the drug out of cells, and suboptimal drug penetration into tuberculosis lesions-are likely crucial to the pathogenesis of drug-resistant tuberculosis. These factors have implications for the design of new interventions, drug delivery and dosing mechanisms, and public health policy. We discuss epidemiology and transmission dynamics, including new insights into the fundamental biology of transmission, and we review the utility of newer diagnostic tools, including molecular tests and next-generation whole-genome sequencing, and their potential for clinical effectiveness. Relevant research priorities are highlighted, including optimal medical and surgical management, the role of newer and repurposed drugs (including bedaquiline, delamanid, and linezolid), pharmacokinetic and pharmacodynamic considerations, preventive strategies (such as prophylaxis in MDR and XDR contacts), palliative and patient-orientated care aspects, and medicolegal and ethical issues.

Cost-effectiveness and resource implications of aggressive action on tuberculosis in China, India, and South Africa: a combined analysis of nine models

BACKGROUND

The post-2015 End TB Strategy sets global targets of reducing tuberculosis incidence by 50% and mortality by 75% by 2025. We aimed to assess resource requirements and cost-effectiveness of strategies to achieve these targets in China, India, and South Africa.

METHODS

We examined intervention scenarios developed in consultation with country stakeholders, which scaled up existing interventions to high but feasible coverage by 2025. Nine independent modelling groups collaborated to estimate policy outcomes, and we estimated the cost of each scenario by synthesising service use estimates, empirical cost data, and expert opinion on implementation strategies. We estimated health effects (ie, disability-adjusted life-years averted) and resource implications for 2016-35, including patient-incurred costs. To assess resource requirements and cost-effectiveness, we compared scenarios with a base case representing continued current practice.

FINDINGS

Incremental tuberculosis service costs differed by scenario and country, and in some cases they more than doubled existing funding needs. In general, expansion of tuberculosis services substantially reduced patient-incurred costs and, in India and China, produced net cost savings for most interventions under a societal perspective. In all three countries, expansion of access to care produced substantial health gains. Compared with current practice and conventional cost-effectiveness thresholds, most intervention approaches seemed highly cost-effective.

INTERPRETATION

Expansion of tuberculosis services seems cost-effective for high-burden countries and could generate substantial health and economic benefits for patients, although substantial new funding would be required. Further work to determine the optimal intervention mix for each country is necessary.

FUNDING

Bill & Melinda Gates Foundation.

Feasibility of achieving the 2025 WHO global tuberculosis targets in South Africa, China, and India: a combined analysis of 11 mathematical models

Background

The post-2015 End TB Strategy proposes targets of 50% reduction in tuberculosis incidence and 75% reduction in mortality from tuberculosis by 2025. We aimed to assess whether these targets are feasible in three high-burden countries with contrasting epidemiology and previous programmatic achievements.

Methods

11 independently developed mathematical models of tuberculosis transmission projected the epidemiological impact of currently available tuberculosis interventions for prevention, diagnosis, and treatment in China, India, and South Africa. Models were calibrated with data on tuberculosis incidence and mortality in 2012. Representatives from national tuberculosis programmes and the advocacy community provided distinct country-specific intervention scenarios, which included screening for symptoms, active case finding, and preventive therapy.

Findings

Aggressive scale-up of any single intervention scenario could not achieve the post-2015 End TB Strategy targets in any country. However, the models projected that, in the South Africa national tuberculosis programme scenario, a combination of continuous isoniazid preventive therapy for individuals on antiretroviral therapy, expanded facility-based screening for symptoms of tuberculosis at health centres, and improved tuberculosis care could achieve a 55% reduction in incidence (range 31–62%) and a 72% reduction in mortality (range 64–82%) compared with 2015 levels. For India, and particularly for China, full scale-up of all interventions in tuberculosis-programme performance fell short of the 2025 targets, despite preventing a cumulative 3·4 million cases. The advocacy scenarios illustrated the high impact of detecting and treating latent tuberculosis.

Interpretation

Major reductions in tuberculosis burden seem possible with current interventions. However, additional interventions, adapted to country-specific tuberculosis epidemiology and health systems, are needed to reach the post-2015 End TB Strategy targets at country level.

Funding

Bill and Melinda Gates Foundation