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Ross JM, Greene C, Broshkevitch CJ, Dowdy DW, van Heerden A, Heitner J, Rao DW, Roberts DA, Shapiro AE, Zabinsky ZB, Barnabas RV. Preventing tuberculosis with community-based care in an HIV-endemic setting: a modelling analysis. J Int AIDS Soc 2024; 27:e26272. [PMID: 38861426 PMCID: PMC11166187 DOI: 10.1002/jia2.26272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 04/30/2024] [Indexed: 06/13/2024] Open
Abstract
INTRODUCTION Antiretroviral therapy (ART) and tuberculosis preventive treatment (TPT) both prevent tuberculosis (TB) disease and deaths among people living with HIV. Differentiated care models, including community-based care, can increase the uptake of ART and TPT to prevent TB in settings with a high burden of HIV-associated TB, particularly among men. METHODS We developed a gender-stratified dynamic model of TB and HIV transmission and disease progression among 100,000 adults ages 15-59 in KwaZulu-Natal, South Africa. We drew model parameters from a community-based ART initiation and resupply trial in sub-Saharan Africa (Delivery Optimization for Antiretroviral Therapy, DO ART) and other scientific literature. We simulated the impacts of community-based ART and TPT care programmes during 2018-2027, assuming that community-based ART and TPT care were scaled up to similar levels as in the DO ART trial (i.e. ART coverage increasing from 49% to 82% among men and from 69% to 83% among women) and sustained for 10 years. We projected the number of TB cases, deaths and disability-adjusted life years (DALYs) averted relative to standard, clinic-based care. We calculated programme costs and incremental cost-effectiveness ratios from the provider perspective. RESULTS If community-based ART care could be implemented with similar effectiveness to the DO ART trial, increased ART coverage could reduce TB incidence by 27.0% (range 21.3%-34.1%) and TB mortality by 34.6% (range 24.8%-42.2%) after 10 years. Increasing both ART and TPT uptake through community-based ART with TPT care could reduce TB incidence by 29.7% (range 23.9%-36.0%) and TB mortality by 36.0% (range 26.9%-43.8%). Community-based ART with TPT care reduced gender disparities in TB mortality rates, with a projected 54 more deaths annually among men than women (range 11-103) after 10 years of community-based care versus 109 (range 41-182) in standard care. Over 10 years, the mean cost per DALY averted by community-based ART with TPT care was $846 USD (range $709-$1012). CONCLUSIONS By substantially increasing coverage of ART and TPT, community-based care for people living with HIV could reduce TB incidence and mortality in settings with high burdens of HIV-associated TB and reduce TB gender disparities.
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Affiliation(s)
- Jennifer M. Ross
- Division of Allergy and Infectious DiseasesDepartment of MedicineUniversity of WashingtonSeattleWashingtonUSA
| | - Chelsea Greene
- Department of Industrial and Systems EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Cara J. Broshkevitch
- Department of EpidemiologyUniversity of North CarolinaChapel HillNorth CarolinaUSA
| | - David W. Dowdy
- Department of EpidemiologyJohns Hopkins Bloomberg School of Public HealthBaltimoreMarylandUSA
| | - Alastair van Heerden
- Centre for Community Based ResearchHuman Sciences Research CouncilPietermaritzburgSouth Africa
- SAMRC/Wits Developmental Pathways for Health Research UnitUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Jesse Heitner
- Division of Infectious DiseasesMassachusetts General HospitalBostonMassachusettsUSA
| | - Darcy W. Rao
- Bill & Melinda Gates FoundationSeattleWashingtonUSA
| | - D. Allen Roberts
- Department of EpidemiologyUniversity of WashingtonSeattleWashingtonUSA
| | - Adrienne E. Shapiro
- Division of Allergy and Infectious DiseasesDepartment of MedicineUniversity of WashingtonSeattleWashingtonUSA
- Department of Global HealthUniversity of WashingtonSeattleWashingtonUSA
| | - Zelda B. Zabinsky
- Department of Industrial and Systems EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Ruanne V. Barnabas
- Division of Infectious DiseasesMassachusetts General HospitalBostonMassachusettsUSA
- Harvard Medical SchoolBostonMassachusettsUSA
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Fuller NM, McQuaid CF, Harker MJ, Weerasuriya CK, McHugh TD, Knight GM. Mathematical models of drug-resistant tuberculosis lack bacterial heterogeneity: A systematic review. PLoS Pathog 2024; 20:e1011574. [PMID: 38598556 PMCID: PMC11060536 DOI: 10.1371/journal.ppat.1011574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 04/30/2024] [Accepted: 03/25/2024] [Indexed: 04/12/2024] Open
Abstract
Drug-resistant tuberculosis (DR-TB) threatens progress in the control of TB. Mathematical models are increasingly being used to guide public health decisions on managing both antimicrobial resistance (AMR) and TB. It is important to consider bacterial heterogeneity in models as it can have consequences for predictions of resistance prevalence, which may affect decision-making. We conducted a systematic review of published mathematical models to determine the modelling landscape and to explore methods for including bacterial heterogeneity. Our first objective was to identify and analyse the general characteristics of mathematical models of DR-mycobacteria, including M. tuberculosis. The second objective was to analyse methods of including bacterial heterogeneity in these models. We had different definitions of heterogeneity depending on the model level. For between-host models of mycobacterium, heterogeneity was defined as any model where bacteria of the same resistance level were further differentiated. For bacterial population models, heterogeneity was defined as having multiple distinct resistant populations. The search was conducted following PRISMA guidelines in five databases, with studies included if they were mechanistic or simulation models of DR-mycobacteria. We identified 195 studies modelling DR-mycobacteria, with most being dynamic transmission models of non-treatment intervention impact in M. tuberculosis (n = 58). Studies were set in a limited number of specific countries, and 44% of models (n = 85) included only a single level of "multidrug-resistance (MDR)". Only 23 models (8 between-host) included any bacterial heterogeneity. Most of these also captured multiple antibiotic-resistant classes (n = 17), but six models included heterogeneity in bacterial populations resistant to a single antibiotic. Heterogeneity was usually represented by different fitness values for bacteria resistant to the same antibiotic (61%, n = 14). A large and growing body of mathematical models of DR-mycobacterium is being used to explore intervention impact to support policy as well as theoretical explorations of resistance dynamics. However, the majority lack bacterial heterogeneity, suggesting that important evolutionary effects may be missed.
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Affiliation(s)
- Naomi M. Fuller
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher F. McQuaid
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin J. Harker
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chathika K. Weerasuriya
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Timothy D. McHugh
- UCL Centre for Clinical Microbiology, Division of Infection & Immunity, Royal Free Campus, University College London, London, United Kingdom
| | - Gwenan M. Knight
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Xu C, Cheng K, Wang Y, Liu M, Wang X, Yang Z, Guo S. Analysis of the current status of TB transmission in China based on an age heterogeneity model. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:19232-19253. [PMID: 38052598 DOI: 10.3934/mbe.2023850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Tuberculosis (TB) is an infectious disease transmitted through the respiratory system. China is one of the countries with a high burden of TB. Since 2004, an average of more than 800,000 cases of active TB has been reported each year in China. Analyzing the case data from 2004 to 2018, we found significant differences in TB incidence by age group. A model of TB is put forward to explore the effect of age heterogeneity on TB transmission. The nonlinear least squares method is used to obtain the key parameters in the model, and the basic reproduction number Rv = 0.8017 is calculated and the sensitivity analysis of Rv to the parameters is given. The simulation results show that reducing the number of new infections in the elderly population and increasing the recovery rate of elderly patients with the disease could significantly reduce the transmission of TB. Furthermore, the feasibility of achieving the goals of the World Health Organization (WHO) End TB Strategy in China is assessed, and we obtained that with existing TB control measures it will take another 30 years for China to reach the WHO goal to reduce 90% of the number of new cases by the year 2049. However, in theory it is feasible to reach the WHO strategic goal of ending TB by 2035 if the group contact rate in the elderly population can be reduced, though it is difficult to reduce the contact rate.
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Affiliation(s)
- Chuanqing Xu
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
| | - Kedeng Cheng
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
| | - Yu Wang
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
| | - Maoxing Liu
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
| | - Xiaojing Wang
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
| | - Zhen Yang
- Beijing Changping District TB Control Center, 102202, China
| | - Songbai Guo
- School of Science, Beijing University of Civil Engineering and Architecture, 100044, China
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Ross JM, Greene C, Bayer CJ, Dowdy DW, van Heerden A, Heitner J, Rao DW, Roberts DA, Shapiro AE, Zabinsky ZB, Barnabas RV. Preventing tuberculosis with community-based care in an HIV-endemic setting: a modeling analysis. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.21.23294380. [PMID: 37662260 PMCID: PMC10473784 DOI: 10.1101/2023.08.21.23294380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Introduction Antiretroviral therapy (ART) and TB preventive treatment (TPT) both prevent tuberculosis (TB) disease and deaths among people living with HIV. Differentiated care models, including community-based care, can increase uptake of ART and TPT to prevent TB in settings with a high burden of HIV-associated TB, particularly among men. Methods We developed a gender-stratified dynamic model of TB and HIV transmission and disease progression among 100,000 adults ages 15-59 in KwaZulu-Natal, South Africa. We drew model parameters from a community-based ART initiation and resupply trial in sub-Saharan Africa (Delivery Optimization for Antiretroviral Therapy, DO ART) and other scientific literature. We simulated the impacts of community-based ART and TPT care programs during 2018-2027, assuming that community-based ART and TPT care were scaled up to similar levels as in the DO ART trial (i.e., ART coverage increasing from 49% to 82% among men and from 69% to 83% among women) and sustained for ten years. We projected the number of TB cases, deaths, and disability-adjusted life years (DALYs) averted relative to standard, clinic-based care. We calculated program costs and incremental cost-effectiveness ratios from the provider perspective. Results If community-based ART care could be implemented with similar effectiveness to the DO ART trial, increased ART coverage could reduce TB incidence by 27.0% (range 21.3% - 34.1%) and TB mortality by 36.0% (range 26.9% - 43.8%) after ten years. Increasing both ART and TPT uptake through community-based ART with TPT care could reduce TB incidence by 29.7% (range 23.9% - 36.0%) and TB mortality by 36.0% (range 26.9% - 43.8%). Community-based ART with TPT care reduced gender disparities in TB mortality rates by reducing TB mortality among men by a projected 39.8% (range 32.2% - 46.3%) and by 30.9% (range 25.3% - 36.5%) among women. Over ten years, the mean cost per DALY averted by community-based ART with TPT care was $846 USD (range $709 - $1,012). Conclusions By substantially increasing coverage of ART and TPT, community-based care for people living with HIV could reduce TB incidence and mortality in settings with high burdens of HIV-associated TB and reduce TB gender disparities.
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Affiliation(s)
- Jennifer M. Ross
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, USA
| | - Chelsea Greene
- Department of Industrial and Systems Engineering, University of Washington, Seattle, USA
| | - Cara J. Bayer
- Department of Epidemiology, University of North Carolina, Chapel Hill, USA
| | - David W. Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Alastair van Heerden
- Centre for Community Based Research, Human Sciences Research Council, Pietermaritzburg, South Africa
- SAMRC/Wits Developmental Pathways for Health Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Jesse Heitner
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA
| | | | - D. Allen Roberts
- Department of Epidemiology, University of Washington, Seattle, USA
| | - Adrienne E. Shapiro
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, USA
- Department of Global Health, University of Washington, Seattle, USA
| | - Zelda B. Zabinsky
- Department of Industrial and Systems Engineering, University of Washington, Seattle, USA
| | - Ruanne V. Barnabas
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, USA
- Harvard Medical School, Boston, USA
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Heidary M, Shirani M, Moradi M, Goudarzi M, Pouriran R, Rezaeian T, Khoshnood S. Tuberculosis challenges: Resistance, co-infection, diagnosis, and treatment. Eur J Microbiol Immunol (Bp) 2022; 12:1-17. [PMID: 35420996 PMCID: PMC9036649 DOI: 10.1556/1886.2021.00021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/10/2022] [Indexed: 01/23/2023] Open
Abstract
Early diagnosis of tuberculosis (TB), followed by effective treatment, is the cornerstone of global TB control efforts. An estimated 3 million cases of TB remain undetected each year. Early detection and effective management of TB can prevent severe disease and reduce mortality and transmission. Intrinsic and acquired drug resistance of Mycobacterium tuberculosis (MTB) severely restricted the anti-TB therapeutic options, and public health policies are required to preserve the new medications to treat TB. In addition, TB and HIV frequently accelerate the progression of each other, and one disease can enhance the other effect. Overall, TB-HIV co-infections show an adverse bidirectional interaction. For HIV-infected patients, the risk of developing TB disease is approximately 22 times higher than for persons with a protective immune response. Analysis of the current TB challenges is critical to meet the goals of the end TB strategy and can go a long way in eradicating the disease. It provides opportunities for global TB control and demonstrates the efforts required to accelerate eliminating TB. This review will discuss the main challenges of the TB era, including resistance, co-infection, diagnosis, and treatment.
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Affiliation(s)
- Mohsen Heidary
- Department of Laboratory Sciences, School of Paramedical Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Maryam Shirani
- Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Melika Moradi
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mehdi Goudarzi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ramin Pouriran
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tayebe Rezaeian
- Department of Microbiology and Virology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Khoshnood
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
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Shrestha S, Kendall EA, Chang R, Joseph R, Kasaie P, Gillini L, Fojo AT, Campbell M, Arinaminpathy N, Dowdy DW. Achieving a "step change" in the tuberculosis epidemic through comprehensive community-wide intervention: a model-based analysis. BMC Med 2021; 19:244. [PMID: 34645429 PMCID: PMC8514283 DOI: 10.1186/s12916-021-02110-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/27/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Global progress towards reducing tuberculosis (TB) incidence and mortality has consistently lagged behind the World Health Organization targets leading to a perception that large reductions in TB burden cannot be achieved. However, several recent and historical trials suggest that intervention efforts that are comprehensive and intensive can have a substantial epidemiological impact. We aimed to quantify the potential epidemiological impact of an intensive but realistic, community-wide campaign utilizing existing tools and designed to achieve a "step change" in the TB burden. METHODS We developed a compartmental model that resembled TB transmission and epidemiology of a mid-sized city in India, the country with the greatest absolute TB burden worldwide. We modeled the impact of a one-time, community-wide screening campaign, with treatment for TB disease and preventive therapy for latent TB infection (LTBI). This one-time intervention was followed by the strengthening of the tuberculosis-related health system, potentially facilitated by leveraging the one-time campaign. We estimated the tuberculosis cases and deaths that could be averted over 10 years using this comprehensive approach and assessed the contributions of individual components of the intervention. RESULTS A campaign that successfully screened 70% of the adult population for active and latent tuberculosis and subsequently reduced diagnostic and treatment delays and unsuccessful treatment outcomes by 50% was projected to avert 7800 (95% range 5450-10,200) cases and 1710 (1290-2180) tuberculosis-related deaths per 1 million population over 10 years. Of the total averted deaths, 33.5% (28.2-38.3) were attributable to the inclusion of preventive therapy and 52.9% (48.4-56.9) to health system strengthening. CONCLUSIONS A one-time, community-wide mass campaign, comprehensively designed to detect, treat, and prevent tuberculosis with currently existing tools can have a meaningful and long-lasting epidemiological impact. Successful treatment of LTBI is critical to achieving this result. Health system strengthening is essential to any effort to transform the TB response.
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Affiliation(s)
- Sourya Shrestha
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
| | | | | | - Roy Joseph
- Clinton Health Access Initiative, Boston, USA
| | - Parastu Kasaie
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | | | | | | | | | - David W Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
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Economic and modeling evidence for tuberculosis preventive therapy among people living with HIV: A systematic review and meta-analysis. PLoS Med 2021; 18:e1003712. [PMID: 34520463 PMCID: PMC8439468 DOI: 10.1371/journal.pmed.1003712] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 06/27/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Human immunodeficiency virus (HIV) is the strongest known risk factor for tuberculosis (TB) through its impairment of T-cell immunity. Tuberculosis preventive treatment (TPT) is recommended for people living with HIV (PLHIV) by the World Health Organization, as it significantly reduces the risk of developing TB disease. We conducted a systematic review and meta-analysis of modeling studies to summarize projected costs, risks, benefits, and impacts of TPT use among PLHIV on TB-related outcomes. METHODS AND FINDINGS We searched MEDLINE, Embase, and Web of Science from inception until December 31, 2020. Two reviewers independently screened titles, abstracts, and full texts; extracted data; and assessed quality. Extracted data were summarized using descriptive analysis. We performed quantile regression and random effects meta-analysis to describe trends in cost, effectiveness, and cost-effectiveness outcomes across studies and identified key determinants of these outcomes. Our search identified 6,615 titles; 61 full texts were included in the final review. Of the 61 included studies, 31 reported both cost and effectiveness outcomes. A total of 41 were set in low- and middle-income countries (LMICs), while 12 were set in high-income countries (HICs); 2 were set in both. Most studies considered isoniazid (INH)-based regimens 6 to 2 months long (n = 45), or longer than 12 months (n = 11). Model parameters and assumptions varied widely between studies. Despite this, all studies found that providing TPT to PLHIV was predicted to be effective at averting TB disease. No TPT regimen was substantially more effective at averting TB disease than any other. The cost of providing TPT and subsequent downstream costs (e.g. post-TPT health systems costs) were estimated to be less than $1,500 (2020 USD) per person in 85% of studies that reported cost outcomes (n = 36), regardless of study setting. All cost-effectiveness analyses concluded that providing TPT to PLHIV was potentially cost-effective compared to not providing TPT. In quantitative analyses, country income classification, consideration of antiretroviral therapy (ART) use, and TPT regimen use significantly impacted cost-effectiveness. Studies evaluating TPT in HICs suggested that TPT may be more effective at preventing TB disease than studies evaluating TPT in LMICs; pooled incremental net monetary benefit, given a willingness-to-pay threshold of country-level per capita gross domestic product (GDP), was $271 in LMICs (95% confidence interval [CI] -$81 to $622, p = 0.12) and was $2,568 in HICs (-$32,115 to $37,251, p = 0.52). Similarly, TPT appeared to be more effective at averting TB disease in HICs; pooled percent reduction in active TB incidence was 20% (13% to 27%, p < 0.001) in LMICs and 37% (-34% to 100%, p = 0.13) in HICs. Key limitations of this review included the heterogeneity of input parameters and assumptions from included studies, which limited pooling of effect estimates, inconsistent reporting of model parameters, which limited sample sizes of quantitative analyses, and database bias toward English publications. CONCLUSIONS The body of literature related to modeling TPT among PLHIV is large and heterogeneous, making comparisons across studies difficult. Despite this variability, all studies in all settings concluded that providing TPT to PLHIV is potentially effective and cost-effective for preventing TB disease.
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Ma Y, Xu Y, Cao X, Chen X, Zhong Y. Diagnostic value of interferon- γ release assay in HIV-infected individuals complicated with active tuberculosis: a systematic review and meta-analysis. Epidemiol Infect 2021; 149:e204. [PMID: 34420541 PMCID: PMC8447472 DOI: 10.1017/s0950268821001953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 07/04/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Although the interferon-γ release assay (IGRA) has become a common diagnostic method for tuberculosis, its value in the diagnosis of tuberculosis in human immunodeficiency virus (HIV) seropositive patients remains controversial. Therefore, this systematically reviews the data for exploring the diagnostic value of IGRA in HIV-infected individuals complicated with active tuberculosis, aiming to provide a clinical basis for future clinical diagnosis of the disease. METHODS Relevant studies on IGRA for diagnosing tuberculosis in HIV-infected patients were comprehensively collected from Excerpta Medica Database (EMBASE), Medline, Cochrane Library, Chinese Sci-tech Periodical Full-text Database, Chinese Periodical Full-text Database, China National Knowledge Infrastructure (CNKI) and China Wanfang Data up to July 2020. Subsequently, Stata 15.0, an integrated statistical software, was used to analyse the sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) to create receiver operator characteristic (ROC) curves. RESULTS A total of 18 high-quality articles were selected, including 20 studies, 11 of which were related to QuantiFERON-TB Gold In-Tube (QFT-GIT) and nine to T-SPOT.TB. The meta-analysis indicated that the pooled sensitivity = 0.75 (95% CI 0.63-0.85), the pooled specificity = 0.82 (95% CI 0.66-0.92), PLR = 4.25 (95% CI 1.97-9.18), NLR = 0.30 (95% CI 0.18-0.50), DOR = 14.21 (95% CI 4.38-46.09) and the area under summary ROC curve was 0.85 (95% CI 0.81-0.88). CONCLUSION IGRA has a good diagnostic value and therefore can aid in the preliminary screening of active tuberculosis in HIV-infected individuals. Its diagnostic effectiveness can be improved by modifying and optimizing the assay design.
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Affiliation(s)
- Yiyun Ma
- Department of Laboratory Medicine, Hainan General Hospital, Haikou, Hainan, China
| | - Yuni Xu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Xiaoqiang Cao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Xiaojuan Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Yeteng Zhong
- Department of Laboratory Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
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Ricks S, Denkinger CM, Schumacher SG, Hallett TB, Arinaminpathy N. The potential impact of urine-LAM diagnostics on tuberculosis incidence and mortality: A modelling analysis. PLoS Med 2020; 17:e1003466. [PMID: 33306694 PMCID: PMC7732057 DOI: 10.1371/journal.pmed.1003466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 11/13/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Lateral flow urine lipoarabinomannan (LAM) tests could offer important new opportunities for the early detection of tuberculosis (TB). The currently licensed LAM test, Alere Determine TB LAM Ag ('LF-LAM'), performs best in the sickest people living with HIV (PLHIV). However, the technology continues to improve, with newer LAM tests, such as Fujifilm SILVAMP TB LAM ('SILVAMP-LAM') showing improved sensitivity, including amongst HIV-negative patients. It is important to anticipate the epidemiological impact that current and future LAM tests may have on TB incidence and mortality. METHODS AND FINDINGS Concentrating on South Africa, we examined the impact that widening LAM test eligibility would have on TB incidence and mortality. We developed a mathematical model of TB transmission to project the impact of LAM tests, distinguishing 'current' tests (with sensitivity consistent with LF-LAM), from hypothetical 'future' tests (having sensitivity consistent with SILVAMP-LAM). We modelled the impact of both tests, assuming full adoption of the 2019 WHO guidelines for the use of these tests amongst those receiving HIV care. We also simulated the hypothetical deployment of future LAM tests for all people presenting to care with TB symptoms, not restricted to PLHIV. Our model projects that 2,700,000 (95% credible interval [CrI] 2,000,000-3,600,000) and 420,000 (95% CrI 350,000-520,000) cumulative TB incident cases and deaths, respectively, would occur between 2020 and 2035 if the status quo is maintained. Relative to this comparator, current and future LAM tests would respectively avert 54 (95% CrI 33-86) and 90 (95% CrI 55-145) TB deaths amongst inpatients between 2020 and 2035, i.e., reductions of 5% (95% CrI 4%-6%) and 9% (95% CrI 7%-11%) in inpatient TB mortality. This impact in absolute deaths averted doubles if testing is expanded to include outpatients, yet remains <1% of country-level TB deaths. Similar patterns apply to incidence results. However, deploying a future LAM test for all people presenting to care with TB symptoms would avert 470,000 (95% CrI 220,000-870,000) incident TB cases (18% reduction, 95% CrI 9%-29%) and 120,000 (95% CrI 69,000-210,000) deaths (30% reduction, 95% CrI 18%-44%) between 2020 and 2035. Notably, this increase in impact arises largely from diagnosis of TB amongst those with HIV who are not yet in HIV care, and who would thus be ineligible for a LAM test under current guidelines. Qualitatively similar results apply under an alternative comparator assuming expanded use of GeneXpert MTB/RIF ('Xpert') for TB diagnosis. Sensitivity analysis demonstrates qualitatively similar results in a setting like Kenya, which also has a generalised HIV epidemic, but a lower burden of HIV/TB coinfection. Amongst limitations of this analysis, we do not address the cost or cost-effectiveness of future tests. Our model neglects drug resistance and focuses on the country-level epidemic, thus ignoring subnational variations in HIV and TB burden. CONCLUSIONS These results suggest that LAM tests could have an important effect in averting TB deaths amongst PLHIV with advanced disease. However, achieving population-level impact on the TB epidemic, even in high-HIV-burden settings, will require future LAM tests to have sufficient performance to be deployed more broadly than in HIV care.
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Affiliation(s)
- Saskia Ricks
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
- * E-mail:
| | - Claudia M. Denkinger
- Center of Infectious Disease, University of Heidelberg, Heidelberg, Germany
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | | | - Timothy B. Hallett
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Nimalan Arinaminpathy
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
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10
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Trauer JM, Dodd PJ, Gomes MGM, Gomez GB, Houben RMGJ, McBryde ES, Melsew YA, Menzies NA, Arinaminpathy N, Shrestha S, Dowdy DW. The Importance of Heterogeneity to the Epidemiology of Tuberculosis. Clin Infect Dis 2020; 69:159-166. [PMID: 30383204 PMCID: PMC6579955 DOI: 10.1093/cid/ciy938] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/31/2018] [Indexed: 12/23/2022] Open
Abstract
Although less well-recognized than for other infectious diseases, heterogeneity is a defining feature of tuberculosis (TB) epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment, and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming that average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants, or comorbidities could improve efficiency, but raise ethical and equity considerations.
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Affiliation(s)
- James M Trauer
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Peter J Dodd
- Health Economic and Decision Science, University of Sheffield, United Kingdom
| | - M Gabriela M Gomes
- Liverpool School of Tropical Medicine, United Kingdom.,CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Portugal
| | - Gabriela B Gomez
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Rein M G J Houben
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, United Kingdom.,Infectious Disease Epidemiology Department, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Emma S McBryde
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Queensland
| | - Yayehirad A Melsew
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Nicolas A Menzies
- Department of Global Health and Population, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Nimalan Arinaminpathy
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Sourya Shrestha
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - David W Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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11
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Bracchi M, van Halsema C, Post F, Awosusi F, Barbour A, Bradley S, Coyne K, Dixon-Williams E, Freedman A, Jelliman P, Khoo S, Leen C, Lipman M, Lucas S, Miller R, Seden K, Pozniak A. British HIV Association guidelines for the management of tuberculosis in adults living with HIV 2019. HIV Med 2020; 20 Suppl 6:s2-s83. [PMID: 31152481 DOI: 10.1111/hiv.12748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
| | - Clare van Halsema
- North Manchester General Hospital, Liverpool School of Tropical Medicine
| | - Frank Post
- King's College Hospital NHS Foundation Trust
| | | | | | | | | | | | | | - Pauline Jelliman
- Royal Liverpool and Broadgreen University Hospital Trust, NHIVNA
| | | | | | | | | | | | | | - Anton Pozniak
- Chelsea and Westminster Hospital NHS Foundation Trust, London School of Hygiene and Tropical Medicine
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12
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Ssebuliba DM, Ouifki R. Effect of mixed infection on TB dynamics. INT J BIOMATH 2019. [DOI: 10.1142/s179352451950061x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Poor living conditions, overcrowding and strain diversity are some of the factors that influence mixed infection in Tuberculosis (TB) at the population level. We formulate a mathematical model for mixed infection in TB using nonlinear ordinary differential equations where such factors were represented as probabilities of acquiring mixed infection. A qualitative analysis of the model shows that it exhibits multiple endemic equilibria and backward bifurcation for certain parameter values. The reactivation rate and transmission rate of individuals with mixed infection were of importance as well as the probabilities for latent individuals to acquire mixed infection. We calculate the prevalence of mixed infection from the model and the effect of mixed infection on TB incidence, TB prevalence and Mycobacterium tuberculosis (MTB) infection rate. Numerical simulations show that mixed infection may explain high TB incidences in areas which have a high strain diversity, poor living conditions and are overcrowded even without HIV.
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Affiliation(s)
- Doreen Mbabazi Ssebuliba
- Faculty of Science, Kabale University, P. O. Box 317, Kabale, Uganda
- South African Centre for Epidemiological Modelling, and Analysis, 19 Jonkershoek, Mostertdrift, Stellenbosch, 7600, Cape Town, Western Cape, South Africa
| | - Rachid Ouifki
- South African Centre for Epidemiological Modelling, and Analysis, 19 Jonkershoek, Mostertdrift, Stellenbosch, 7600, Cape Town, Western Cape, South Africa
- Department of Mathematics and Applied Mathematics, University of Pretoria, Private bag X20, Hatfield, 0028 Pretoria, South Africa
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13
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Niewiadomska AM, Jayabalasingham B, Seidman JC, Willem L, Grenfell B, Spiro D, Viboud C. Population-level mathematical modeling of antimicrobial resistance: a systematic review. BMC Med 2019; 17:81. [PMID: 31014341 PMCID: PMC6480522 DOI: 10.1186/s12916-019-1314-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/25/2019] [Indexed: 12/13/2022] Open
Abstract
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.
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Affiliation(s)
- Anna Maria Niewiadomska
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | - Bamini Jayabalasingham
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.,Present Address: Elsevier Inc., 230 Park Ave, Suite B00, New York, NY, 10169, USA
| | - Jessica C Seidman
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | | | - Bryan Grenfell
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.,Princeton University, Princeton, NJ, USA
| | - David Spiro
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA
| | - Cecile Viboud
- Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, USA.
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14
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Wang Y, Wu Q, Zhang W, Zhang N. Tuberculosis and HIV Coinfection–the Challenge in the Prevention, Detection and Treatment of Tuberculosis. Curr Bioinform 2019. [DOI: 10.2174/1574893613666180621153734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Tuberculosis (TB) is still a major public health concern world-wide. The
increasing global burden of TB is linked to HIV infection. HIV-TB coinfection has also
conditioned clinical aspects of the TB. Since the HIV is beginning in the 1980s, the HIV infection
poses a significant challenge in global TB control.
Objective:
In this review we focused on the challenges of epidemiological and clinical feature of
tuberculosis presented by the HIV coinfection.
Method:
The article consists of a summary of the most important effects presented by the HIV
coinfection on epidemiological and clinical feature of tuberculosis. The article analyzes and
summary the causes for these challenges.
Results:
The major challenges to strategy of TB control and clinical feature of TB-HIV coinfection
are presented in this paper.
Conclusion:
HIV/TB co-infection is synergic, interactive and reciprocal with significant impact.
The infection of HIV and Mtb affect each other and the breakdown the immune function in
TB/HIV coinfected individual. HIV infection has changed the strategy of TB control, however
HIV increases global burden of TB, the reduction in the TB incidence rate is far from sufficient.
Atypically clinical manifestations in TB/HIV co-infected patients and increased MDR-TB and
XDR-TB contribute to the challenges in the diagnosis and treatment. Increased complexity of
managing patients requires expertise in the clinical m knowledge. The focused efforts to control
HIV-related TB are of great urgency. These findings will provide insight into the prevention,
detection and treatment of tuberculosis and will guide advances towards tuberculosis control.
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Affiliation(s)
- Yiyi Wang
- TCM Key Research Laboratory for Infectious Disease Prevention for State Administration of Traditional Chinese Medicine, China
| | - Qi Wu
- TCM Key Research Laboratory for Infectious Disease Prevention for State Administration of Traditional Chinese Medicine, China
| | - Wei Zhang
- Clinical and Research Center of Infectious Diseases Beijing Ditan Hospital, Capital Medical University, 100015, Peiking, China
| | - Ning Zhang
- Department of Biomedical Engineering, Tianjin Key Lab of Biomedical Engineering Measurement, Tianjin University, Tianjin, China
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15
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Nurtay A, Hennessy MG, Sardanyés J, Alsedà L, Elena SF. Theoretical conditions for the coexistence of viral strains with differences in phenotypic traits: a bifurcation analysis. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181179. [PMID: 30800366 PMCID: PMC6366233 DOI: 10.1098/rsos.181179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
We investigate the dynamics of a wild-type viral strain which generates mutant strains differing in phenotypic properties for infectivity, virulence and mutation rates. We study, by means of a mathematical model and bifurcation analysis, conditions under which the wild-type and mutant viruses, which compete for the same host cells, can coexist. The coexistence conditions are formulated in terms of the basic reproductive numbers of the strains, a maximum value of the mutation rate and the virulence of the pathogens. The analysis reveals that parameter space can be divided into five regions, each with distinct dynamics, that are organized around degenerate Bogdanov-Takens and zero-Hopf bifurcations, the latter of which gives rise to a curve of transcritical bifurcations of periodic orbits. These results provide new insights into the conditions by which viral populations may contain multiple coexisting strains in a stable manner.
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Affiliation(s)
- Anel Nurtay
- Centre de Recerca Matemàtica, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Departament de Matemàtiques, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Instituto de Biología Integrativa de Sistemas, CSIC-Universitat de València, Parc Científic UV, Paterna, València 46980, Spain
| | - Matthew G. Hennessy
- Centre de Recerca Matemàtica, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
| | - Josep Sardanyés
- Centre de Recerca Matemàtica, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
| | - Lluís Alsedà
- Centre de Recerca Matemàtica, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
- Departament de Matemàtiques, Universitat Autònoma de Barcelona, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Spain
| | - Santiago F. Elena
- Instituto de Biología Integrativa de Sistemas, CSIC-Universitat de València, Parc Científic UV, Paterna, València 46980, Spain
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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16
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Incipient and Subclinical Tuberculosis: a Clinical Review of Early Stages and Progression of Infection. Clin Microbiol Rev 2018; 31:31/4/e00021-18. [PMID: 30021818 DOI: 10.1128/cmr.00021-18] [Citation(s) in RCA: 293] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tuberculosis (TB) is the leading infectious cause of mortality worldwide, due in part to a limited understanding of its clinical pathogenic spectrum of infection and disease. Historically, scientific research, diagnostic testing, and drug treatment have focused on addressing one of two disease states: latent TB infection or active TB disease. Recent research has clearly demonstrated that human TB infection, from latent infection to active disease, exists within a continuous spectrum of metabolic bacterial activity and antagonistic immunological responses. This revised understanding leads us to propose two additional clinical states: incipient and subclinical TB. The recognition of incipient and subclinical TB, which helps divide latent and active TB along the clinical disease spectrum, provides opportunities for the development of diagnostic and therapeutic interventions to prevent progression to active TB disease and transmission of TB bacilli. In this report, we review the current understanding of the pathogenesis, immunology, clinical epidemiology, diagnosis, treatment, and prevention of both incipient and subclinical TB, two emerging clinical states of an ancient bacterium.
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17
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Enhancement of Ag85B DNA vaccine immunogenicity against tuberculosis by dissolving microneedles in mice. Vaccine 2018; 36:4471-4476. [DOI: 10.1016/j.vaccine.2018.06.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 06/03/2018] [Accepted: 06/10/2018] [Indexed: 01/22/2023]
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18
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Marx FM, Yaesoubi R, Menzies NA, Salomon JA, Bilinski A, Beyers N, Cohen T. Tuberculosis control interventions targeted to previously treated people in a high-incidence setting: a modelling study. Lancet Glob Health 2018; 6:e426-e435. [PMID: 29472018 PMCID: PMC5849574 DOI: 10.1016/s2214-109x(18)30022-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 12/14/2017] [Accepted: 12/18/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND In high-incidence settings, recurrent disease among previously treated individuals contributes substantially to the burden of incident and prevalent tuberculosis. The extent to which interventions targeted to this high-risk group can improve tuberculosis control has not been established. We aimed to project the population-level effect of control interventions targeted to individuals with a history of previous tuberculosis treatment in a high-incidence setting. METHODS We developed a transmission-dynamic model of tuberculosis and HIV in a high-incidence setting with a population of roughly 40 000 people in suburban Cape Town, South Africa. The model was calibrated to data describing local demography, TB and HIV prevalence, TB case notifications and treatment outcomes using a Bayesian calibration approach. We projected the effect of annual targeted active case finding in all individuals who had previously completed tuberculosis treatment and targeted active case finding combined with lifelong secondary isoniazid preventive therapy. We estimated the effect of these targeted interventions on local tuberculosis incidence, prevalence, and mortality over a 10 year period (2016-25). FINDINGS We projected that, under current control efforts in this setting, the tuberculosis epidemic will remain in slow decline for at least the next decade. Additional interventions targeted to previously treated people could greatly accelerate these declines. We projected that annual targeted active case finding combined with secondary isoniazid preventive therapy in those who previously completed tuberculosis treatment would avert 40% (95% uncertainty interval [UI] 21-56) of incident tuberculosis cases and 41% (16-55) of tuberculosis deaths occurring between 2016 and 2025. INTERPRETATION In this high-incidence setting, the use of targeted active case finding in combination with secondary isoniazid preventive therapy in previously treated individuals could accelerate decreases in tuberculosis morbidity and mortality. Studies to measure cost and resource implications are needed to establish the feasibility of this type of targeted approach for improving tuberculosis control in settings with high tuberculosis and HIV prevalence. FUNDING National Institutes of Health, German Research Foundation.
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Affiliation(s)
- Florian M Marx
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA; Division of Global Health Equity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
| | - Reza Yaesoubi
- Department of Health Policy and Management, Yale School of Public Health, New Haven, CT, USA
| | - Nicolas A Menzies
- Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, USA
| | - Joshua A Salomon
- Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, USA
| | - Alyssa Bilinski
- Interfaculty Initiative in Health Policy, Harvard University, Cambridge, MA, USA
| | - Nulda Beyers
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
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19
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Nagu TJ, Aboud S, Matee MI, Maeurer MJ, Fawzi WW, Mugusi F. Effects of isoniazid resistance on TB treatment outcomes under programmatic conditions in a high-TB and -HIV setting: a prospective multicentre study. J Antimicrob Chemother 2017; 72:876-881. [PMID: 27999054 DOI: 10.1093/jac/dkw503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022] Open
Abstract
Objectives The scale and impact of background isoniazid resistance in TB- and HIV-endemic countries requires definition to improve treatment success and guide the scale-up of isoniazid preventive therapy (IPT). We describe the effects of isoniazid resistance on TB treatment outcomes among patients with or without HIV infection in Dar es Salaam, Tanzania. Methods A multicentre, prospective observational study was conducted among TB patients commencing WHO-recommended first-line TB treatment. In multivariate analysis we ascertained the relationship between isoniazid resistance at presentation with a composite of poor treatment outcomes (death, failure or default from TB therapy). Results Of 861 patients, 250 (29.0%) were HIV infected and 23 (2.7%) had isoniazid resistance. Seven hundred and ninety-seven (92.6%) of the patients were successfully treated and 25 (2.9%) died. Isoniazid resistance [relative risk (RR) = 6.0; 95% CI = 1.9-18.7; P < 0.01] and HIV infection with (RR = 2.3; 95% CI = 1.0-5.2; P = 0.05) or without (RR = 3.1; 95% CI = 1.5-6.2; P < 0.01) ART were independent predictors of poor treatment outcomes. Conclusions Background isoniazid resistance and HIV infection adversely affected TB treatment outcomes. Early laboratory detection of isoniazid resistance is important for successful TB therapy. Studies on the impact of background isoniazid resistance on the efficacy of isoniazid prophylaxis are recommended.
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Affiliation(s)
- Tumaini J Nagu
- Division of Therapeutic Immunology, Department of Laboratory Medicine (LABMED), Karolinska Institutet, Stockholm, Sweden.,Department of Internal Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Said Aboud
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania
| | - Mecky I Matee
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania
| | - Markus J Maeurer
- Division of Therapeutic Immunology, Department of Laboratory Medicine (LABMED), Karolinska Institutet, Stockholm, Sweden
| | - Wafaie W Fawzi
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Ferdinand Mugusi
- Department of Internal Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
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20
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Abstract
BACKGROUND Tuberculosis (TB) is an important cause of illness and death in HIV-positive children living in areas of high TB prevalence. We know that isoniazid prophylaxis prevents TB in HIV-negative children following TB exposure, but there is uncertainty related to its role in TB preventive treatment in HIV-positive children. OBJECTIVES To summarise the effects of TB preventive treatment versus placebo in HIV-positive children with no known TB contact on active TB, death, and reported adverse events. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE/PubMed, Embase and two trial registers up to February 2017. SELECTION CRITERIA We included trials of HIV-positive children with and without known TB exposure, randomized to receive TB preventive treatment or placebo. DATA COLLECTION AND ANALYSIS Two review authors independently used the study selection criteria, assessed risk of bias, and extracted data. We assessed effects using risk, incidence rate and hazard ratios and assessed the certainty of evidence using GRADE. MAIN RESULTS We included three trials, involving 991 participants, below the age of 13 years, from South Africa and Botswana. Children were randomized to isoniazid prophylaxis or placebo, given daily or three times weekly. The median length of follow-up ranged from 5.7 to 34 months; some were on antiretroviral therapy (ART).In HIV-positive children not on ART, isoniazid prophylaxis may reduce the risk of active TB (hazard ratio (HR) 0.31, 95% confidence interval (CI) 0.11 to 0.87; 1 trial, 240 participants, low certainty evidence), and death (HR 0.46, 95% CI 0.22 to 0.95; 1 trial, 240 participants, low certainty evidence). One trial (182 participants) reported number of children with laboratory adverse events, which was similar between the isoniazid prophylaxis and placebo groups. No clinical adverse events were reported.In HIV-positive children on ART, we do not know if isoniazid prophylaxis reduces the risk of active TB (risk ratio (RR) 0.76, 95% CI 0.50 to 1.14; 3 trials, 737 participants, very low certainty evidence) or death (RR 1.45, 95% CI 0.78 to 2.72; 3 trials, 737 participants, very low certainty evidence). Two trials (714 participants) reported number of clinical adverse events and three trials (795 participants) reported number of laboratory adverse events; for both categories, the number of adverse events were similar between the isoniazid prophylaxis and placebo groups. AUTHORS' CONCLUSIONS Isoniazid prophylaxis given to all children diagnosed with HIV may reduce the risk of active TB and death in HIV-positive children not on ART in studies from Africa. For children on ART, no clear benefit was detected. .
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Affiliation(s)
- Moleen Zunza
- Stellenbosch UniversityCentre for Evidence‐based Health Care, Faculty of Medicine and Health SciencesCape TownSouth Africa
| | - Diane M Gray
- Red Cross War Memorial Children's Hospital and University of Cape TownDepartment of Paediatrics and Child HealthKlipfontein RoadRondeboschCape TownWestern CapeSouth Africa7700
| | - Taryn Young
- Stellenbosch UniversityCentre for Evidence‐based Health Care, Division of Epidemiology and Biostatistics, Faculty of Medicine and Health SciencesPO Box 241Cape TownSouth Africa8000
- South African Medical Research CouncilCochrane South AfricaPO Box 19070TygerbergCape TownSouth Africa7505
| | - Mark Cotton
- Tygerberg Children's HospitalChildren's Infectious Diseases Clinical ResearchJ8 Tygerberg Children's HospitalFrancie van Zijl DriveTygerbergCape ProviceSouth Africa7505
| | - Heather J Zar
- Red Cross Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape TownDepartment of Paediatrics and Child HealthCape TownSouth Africa7700
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21
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Ragonnet R, Trauer JM, Scott N, Meehan MT, Denholm JT, McBryde ES. Optimally capturing latency dynamics in models of tuberculosis transmission. Epidemics 2017. [PMID: 28641948 DOI: 10.1016/j.epidem.2017.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although different structures are used in modern tuberculosis (TB) models to simulate TB latency, it remains unclear whether they are all capable of reproducing the particular activation dynamics empirically observed. We aimed to determine which of these structures replicate the dynamics of progression accurately. We reviewed 88 TB-modelling articles and classified them according to the latency structure employed. We then fitted these different models to the activation dynamics observed from 1352 infected contacts diagnosed in Victoria (Australia) and Amsterdam (Netherlands) to obtain parameter estimates. Six different model structures were identified, of which only those incorporating two latency compartments were capable of reproducing the activation dynamics empirically observed. We found important differences in parameter estimates by age. We also observed marked differences between our estimates and the parameter values used in many previous models. In particular, when two successive latency phases are considered, the first period should have a duration that is much shorter than that used in previous studies. In conclusion, structures incorporating two latency compartments and age-stratification should be employed to accurately replicate the dynamics of TB latency. We provide a catalogue of parameter values and an approach to parameter estimation from empiric data for calibration of future TB-models.
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Affiliation(s)
- Romain Ragonnet
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia; Burnet Institute, Australia.
| | - James M Trauer
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia; School of Population Health and Preventive Medicine, Monash University, Australia; Victorian Tuberculosis Program, Melbourne, Australia
| | - Nick Scott
- Burnet Institute, Australia; School of Population Health and Preventive Medicine, Monash University, Australia
| | - Michael T Meehan
- Australian Institute of Tropical Health and Medicine, James Cook University, Australia
| | - Justin T Denholm
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia; Victorian Tuberculosis Program, Melbourne, Australia; Royal Melbourne Hospital, Melbourne, Australia
| | - Emma S McBryde
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia; Australian Institute of Tropical Health and Medicine, James Cook University, Australia
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22
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Chen F, Yan Q, Yu Y, Wu MX. BCG vaccine powder-laden and dissolvable microneedle arrays for lesion-free vaccination. J Control Release 2017; 255:36-44. [PMID: 28390901 PMCID: PMC6091871 DOI: 10.1016/j.jconrel.2017.03.397] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/17/2017] [Accepted: 03/31/2017] [Indexed: 12/21/2022]
Abstract
Live attenuated Bacille Calmette-Guerin (BCG) bacillus is the only licensed vaccine for tuberculosis prevention worldwide to date. It must be delivered intradermally to be effective, which causes severe skin inflammation and sometimes, permanent scars. To minimize the side effects, we developed a novel microneedle array (MNA) that could deliver live attenuated freeze-dried BCG powder into the epidermis in a painless, lesion-free, and self-applicable fashion. The MNA was fabricated with biocompatible and dissolvable hyaluronic acid with a deep cave formed in the basal portion of each microneedle, into which BCG powder could be packaged directly. Viability of BCG vaccine packaged in the caves and the mechanical strength of the powder-laden MNA did not alter significantly before and after more than two months of storage at room temperature. Following insertion of the MNA into the skin, individual microneedle shafts melted away by interstitial fluid from the epidermis and upper dermis, exposing the powder to epidermal tissues. The powder sucked interstitial fluid, dissolved slowly, and diffused into the epidermis in a day against the interstitial fluid influx. Vaccination with BCG-MNA caused no overt skin irritation, in marked contrast to intradermal vaccination that provoked severe inflammation and bruise. While causing little skin irritation, vaccination efficacy of BCG-MNAs was comparable to that of intradermal immunization whether it was evaluated by humoral or cellular immunity. This powder-laden and dissolvable MNA represents a novel technology to sufficiently deliver live attenuated vaccine powders into the skin.
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Affiliation(s)
- Fan Chen
- Wellman Center for Photomedicine, Massachusetts General Hospital (MGH), Department of Dermatology, Harvard Medical School (HMS), Boston, MA 02114, USA; Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Life Sciences School of Hubei University, 368 Youyi Road, Wuhan 430062, China
| | - Qinying Yan
- Wellman Center for Photomedicine, Massachusetts General Hospital (MGH), Department of Dermatology, Harvard Medical School (HMS), Boston, MA 02114, USA; College of Pharmaceutical Sciences, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310032, China
| | - Yang Yu
- Wellman Center for Photomedicine, Massachusetts General Hospital (MGH), Department of Dermatology, Harvard Medical School (HMS), Boston, MA 02114, USA
| | - Mei X Wu
- Wellman Center for Photomedicine, Massachusetts General Hospital (MGH), Department of Dermatology, Harvard Medical School (HMS), Boston, MA 02114, USA.
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23
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Wikman-Jorgensen PE, Llenas-García J, Pérez-Porcuna TM, Hobbins M, Ehmer J, Mussa MA, Ascaso C. Microscopic observation drug-susceptibility assay vs. Xpert ® MTB/RIF for the diagnosis of tuberculosis in a rural African setting: a cost-utility analysis. Trop Med Int Health 2017; 22:734-743. [PMID: 28380276 DOI: 10.1111/tmi.12879] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To compare the cost-utility of microscopic observation drug-susceptibility assay (MODS) and Xpert® MTB/RIF implementation for tuberculosis (TB) diagnosis in rural northern Mozambique. METHODS Stochastic transmission compartmental TB model from the healthcare provider perspective with parameter input from direct measurements, systematic literature reviews and expert opinion. MODS and Xpert® MTB/RIF were evaluated as replacement test of smear microscopy (SM) or as an add-on test after a negative SM. Costs were calculated in 2013 USD, effects in disability-adjusted life years (DALY). Willingness to pay threshold (WPT) was established at once the per capita Gross National Income of Mozambique. RESULTS MODS as an add-on test to negative SM produced an incremental cost-effectiveness ratio (ICER) of 5647.89USD/DALY averted. MODS as a substitute for SM yielded an ICER of 5374.58USD/DALY averted. Xpert® MTB/RIF as an add-on test to negative SM yielded ICER of 345.71USD/DALY averted. Xpert® MTB/RIF as a substitute for SM obtained an ICER of 122.13USD/DALY averted. TB prevalence and risk of infection were the main factors impacting MODS and Xpert® MTB/RIF ICER in the one-way sensitivity analysis. In the probabilistic sensitivity analysis, Xpert® MTB/RIF was most likely to have an ICER below the WPT, whereas MODS was not. CONCLUSION Our cost-utility analysis favours the implementation of Xpert® MTB/RIF as a replacement of SM for all TB suspects in this rural high TB/HIV prevalence African setting.
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Affiliation(s)
- Philip E Wikman-Jorgensen
- Department of Public Health, University of Barcelona, Barcelona, Spain.,SolidarMed Mozambique, Ancuabe, Mozambique
| | - Jara Llenas-García
- SolidarMed Mozambique, Ancuabe, Mozambique.,Infectious Diseases Unit, Hospital General Universitario de Elche, Alicante, Spain
| | - Tomàs M Pérez-Porcuna
- Department of Public Health, University of Barcelona, Barcelona, Spain.,Research Unit, Paediatrics Department, CAP Valldoreix, Mutua Terrassa Foundation, Mutua Terrassa University Hospital, Terrassa, Catalunya, Spain
| | | | | | - Manuel A Mussa
- Provincial Health Directorate, Operational Research Nucleus of Pemba, Pemba, Mozambique
| | - Carlos Ascaso
- Department of Public Health, University of Barcelona, Barcelona, Spain
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24
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Moualeu DP, Bowong S, Tsanou B, Temgoua A. A patchy model for the transmission dynamics of tuberculosis in sub-Saharan Africa. INTERNATIONAL JOURNAL OF DYNAMICS AND CONTROL 2017; 6:122-139. [PMID: 32288982 PMCID: PMC7133616 DOI: 10.1007/s40435-017-0310-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 01/25/2017] [Accepted: 02/02/2017] [Indexed: 11/30/2022]
Abstract
Tuberculosis (TB) spreads through contact between a susceptible person and smear positive pulmonary TB case (TPM+). The spread of TB is highly dependent on people migration between cities or regions that may have different contact rates and different environmental parameters, leading to different disease spread speed in the population. In this work, a metapopulation model, i.e., networks of populations connected by migratory flows, which overcomes the assumption of homogeneous mixing between different regions was constructed. The TB model was combined to a simple demographic structure for the population living in a multi-patch environment (cities, towns, regions or countries). The model consist of a system of differential equations coupling TB epidemic at different strength and mobility between the patches. Constant recruitment rate, slow and fast progression to the disease, effective chemoprophylaxis, diagnostic and treatment are taken into account to make the model including the reality of people in the sub-Saharan African countries. The basic reproduction number ( R 0 ) was computed and it was demonstrated that the disease-free equilibrium is globally asymptotically stable ifR 0 < 1 . WhenR 0 > 1 , the disease-free equilibrium is unstable and there exists one endemic equilibrium. Moreover, the impact of increasing migration rate between patches on the TB spread was quantified using numerical implementation of the model. Using an example on 15 inter-connected patches on the same road, we demonstrated that most people was most likely to get infected if the disease starts in a patch in the middle than in border patches.
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Affiliation(s)
- D. P. Moualeu
- Institute for Horticultural Production Systems, Vegetable Systems Modelling Section, Faculty of Natural Sciences, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - S. Bowong
- Department of Mathematics and Computer Science, Faculty of Science, University of Douala, PO Box 24157, Douala, Cameroon
- UMI 209 IRD/UPMC UMMISCO, Bondy-France and GRIMCAPE-Cameroon, The African Center of Excellence in Information and Communication Technologies (CETIC), University of Yaounde 1, Yaounde, Cameroon
| | - B. Tsanou
- Department of Mathematics and Computer Science, Faculty of Science, University of Dschang, PO Box 47, Dschang, Cameroon
| | - A. Temgoua
- Department of Mathematics and Computer Science, Faculty of Science, University of Douala, PO Box 24157, Douala, Cameroon
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25
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Gilbert JA, Shenoi SV, Moll AP, Friedland GH, Paltiel AD, Galvani AP. Cost-Effectiveness of Community-Based TB/HIV Screening and Linkage to Care in Rural South Africa. PLoS One 2016; 11:e0165614. [PMID: 27906986 PMCID: PMC5131994 DOI: 10.1371/journal.pone.0165614] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 10/15/2016] [Indexed: 01/08/2023] Open
Abstract
South Africa has one of the highest burdens of TB worldwide, driven by the country's widespread prevalence of HIV, and further complicated by drug resistance. Active case finding within the community, particularly in rural areas where healthcare access is limited, can significantly improve diagnosis and treatment coverage in high-incidence settings. We evaluated the potential health and economic consequences of implementing community-based TB/HIV screening and linkage to care. Using a dynamic model of TB and HIV transmission over a time horizon of 10 years, we compared status quo TB/HIV control to community-based TB/HIV screening at frequencies of once every two years, one year, and six months. We also considered the impact of extending IPT from 36 months for TST positive and 12 months for TST negative or unknown patients (36/12) to lifetime use for all HIV-infected patients. We conducted a probabilistic sensitivity analysis to assess the effect of parameter uncertainty on the cost-effectiveness results. We identified four strategies that saved the most life years for a given outlay: status quo TB/HIV control with 36/12 months of IPT and TB/HIV screening strategies at frequencies of once every two years, one year, and six months with lifetime IPT. All of these strategies were very cost-effective at a threshold of $6,618 per life year saved (the per capita GDP of South Africa). Community-based TB/HIV screening with linkage to care is therefore very cost-effective in rural South Africa.
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Affiliation(s)
- Jennifer A. Gilbert
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
- Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Sheela V. Shenoi
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Anthony P. Moll
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Church of Scotland Hospital, Tugela Ferry, KwaZulu-Natal, South Africa
| | - Gerald H. Friedland
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - A. David Paltiel
- Department of Health Policy and Management, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Alison P. Galvani
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
- Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America
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26
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Benefits of continuous isoniazid preventive therapy may outweigh resistance risks in a declining tuberculosis/HIV coepidemic. AIDS 2016; 30:2715-2723. [PMID: 27782966 DOI: 10.1097/qad.0000000000001235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Extending the duration of isoniazid preventive therapy (IPT) among people living with HIV (PLHIV) may improve its effectiveness at both individual and population levels, but could also increase selective pressure in favor of isoniazid-resistant tuberculosis (TB) strains. The objective of this study was to determine the relative importance of these two effects. METHODS Transmission dynamic model. DESIGN We created a mathematical model of TB transmission incorporating HIV incidence and treatment, mixed strain latent TB infections, and four different phenotypes of TB drug resistance (pan-susceptible, isoniazid monoresistant, rifampicin monoresistant, and multidrug resistant). We used this model to project the effects of IPT duration on the incidence of isoniazid-sensitive and isoniazid-resistant TB as well as mortality among PLHIV. We evaluated the sensitivity of our baseline model, which was calibrated to data from Botswana, to different assumptions about the future trajectory of the TB epidemic. RESULTS Our model suggests that, in the context of a declining TB epidemic such as that currently observed in Botswana, the incidence and mortality benefits of continuous IPT for PLHIV are likely to outweigh the potential resistance risks associated with long-duration IPT. However, should TB epidemics fail to remain in control, as was observed during the initial emergence of HIV, the selective pressure imposed by widespread use of continuous IPT on isoniazid-resistant TB incidence may erode its initial benefits. CONCLUSION Resistance concerns are likely insufficient to rule out use of continuous IPT when coupled with effective TB treatment, case finding, and HIV control.
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27
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Beams AB, Toth DJA, Khader K, Adler FR. Harnessing Intra-Host Strain Competition to Limit Antibiotic Resistance: Mathematical Model Results. Bull Math Biol 2016; 78:1828-1846. [PMID: 27670431 DOI: 10.1007/s11538-016-0201-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 08/25/2016] [Indexed: 11/24/2022]
Abstract
Antibiotic overuse has promoted the spread of antibiotic resistance. To compound the issue, treating individuals dually infected with antibiotic-resistant and antibiotic-vulnerable strains can make their infections completely resistant through competitive release. We formulate mathematical models of transmission dynamics accounting for dual infections and extensions accounting for lag times between infection and treatment or between cure and ending treatment. Analysis using the Next-Generation Matrix reveals how competition within hosts and the costs of resistance determine whether vulnerable and resistant strains persist, coexist, or drive each other to extinction. Invasion analysis predicts that treatment of dually infected cases will promote resistance. By varying antibiotic strength, the models suggest that physicians have two ways to achieve a particular resistance target: prescribe relatively weak antibiotics to everyone infected with an antibiotic-vulnerable strain or give more potent prescriptions to only those patients singly infected with the vulnerable strain after ruling out the possibility of them being dually infected with resistance. Through selectivity and moderation in antibiotic prescription, resistance might be limited.
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Affiliation(s)
- Alexander B Beams
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA.
| | - Damon J A Toth
- Informatics, Decision Enhancement, and Analytical Sciences (IDEAS) 2.0 Center, VA Salt Lake City Health Care System, Salt Lake City, UT, USA.,Division of Epidemiology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Karim Khader
- Informatics, Decision Enhancement, and Analytical Sciences (IDEAS) 2.0 Center, VA Salt Lake City Health Care System, Salt Lake City, UT, USA.,Division of Epidemiology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Frederick R Adler
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA.,Department of Biology, University of Utah, Salt Lake City, UT, USA
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28
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Suzukawa M, Akashi S, Nagai H, Nagase H, Nakamura H, Matsui H, Hebisawa A, Ohta K. Combined Analysis of IFN-γ, IL-2, IL-5, IL-10, IL-1RA and MCP-1 in QFT Supernatant Is Useful for Distinguishing Active Tuberculosis from Latent Infection. PLoS One 2016; 11:e0152483. [PMID: 27035669 PMCID: PMC4817970 DOI: 10.1371/journal.pone.0152483] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/15/2016] [Indexed: 02/01/2023] Open
Abstract
The QuantiFERON®-TB Gold In-Tube test (QFT), an interferon-γ release assay, is used to diagnose Mycobacterium tuberculosis, but its inaccuracy in distinguishing active tuberculosis from latent infection is a major concern. There is thus a need for an easy and accurate tool for achieving that goal in daily clinical settings. This study aimed to identify candidate cytokines for specifically differentiating active tuberculosis from latent infection. Our study population consisted of 31 active TB (tuberculosis) patients, 29 LTBI (latent tuberculosis infection) patients and 10 healthy control subjects. We assayed for 27 cytokines in QFT supernatants of both specific antigen-stimulated blood samples (TBAg) and negative-control samples (Nil). We analyzed their specificities and sensitivities by creating receiver operating characteristic (ROC) curves and measuring the area under those curves (AUCs). In TBAg–Nil supernatants, IL-10, IFN-γ, MCP-1 and IL-1RA showed high AUCs of 0.8120, 0.7842, 0.7419 and 0.7375, respectively. Compared with each cytokine alone, combined assay for these top four cytokines showed positive rates in diagnosing active TB, and GDA analysis revealed that MCP-1 and IL-5 are potent in distinguishing active TB from LTBI, with Wilk’s lambda = 0.718 (p < 0.001). Furthermore, utilizing the unique characteristic of IL-2 that its TBAg–Nil supernatant levels are higher in LTBI compared to active TB, the difference between IFN-γ and IL-2 showed a large AUC of 0.8910. In summary, besides IFN-γ, IL-2, IL-5, IL-10, IL-1RA and MCP-1 in QFT supernatants may be useful for distinguishing active TB from LTBI. Those cytokines may also help us understand the difference in pathogenesis between active TB and LTBI.
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Affiliation(s)
- Maho Suzukawa
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - Shunsuke Akashi
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - Hideaki Nagai
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - Hiroyuki Nagase
- Division of Respiratory Medicine and Allergology, Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Hiroyuki Nakamura
- Department of Environmental and Preventive Medicine, Graduate School of Medical Science, Kanazawa University, Ishikawa, Japan
| | - Hirotoshi Matsui
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - Akira Hebisawa
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - Ken Ohta
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
- * E-mail:
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29
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Pareek M, Greenaway C, Noori T, Munoz J, Zenner D. The impact of migration on tuberculosis epidemiology and control in high-income countries: a review. BMC Med 2016; 14:48. [PMID: 27004556 PMCID: PMC4804514 DOI: 10.1186/s12916-016-0595-5] [Citation(s) in RCA: 169] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/08/2016] [Indexed: 02/08/2023] Open
Abstract
Tuberculosis (TB) causes significant morbidity and mortality in high-income countries with foreign-born individuals bearing a disproportionate burden of the overall TB case burden in these countries. In this review of tuberculosis and migration we discuss the impact of migration on the epidemiology of TB in low burden countries, describe the various screening strategies to address this issue, review the yield and cost-effectiveness of these programs and describe the gaps in knowledge as well as possible future solutions.The reasons for the TB burden in the migrant population are likely to be the reactivation of remotely-acquired latent tuberculosis infection (LTBI) following migration from low/intermediate-income high TB burden settings to high-income, low TB burden countries.TB control in high-income countries has historically focused on the early identification and treatment of active TB with accompanying contact-tracing. In the face of the TB case-load in migrant populations, however, there is ongoing discussion about how best to identify TB in migrant populations. In general, countries have generally focused on two methods: identification of active TB (either at/post-arrival or increasingly pre-arrival in countries of origin) and secondly, conditionally supported by WHO guidance, through identifying LTBI in migrants from high TB burden countries. Although health-economic analyses have shown that TB control in high income settings would benefit from providing targeted LTBI screening and treatment to certain migrants from high TB burden countries, implementation issues and barriers such as sub-optimal treatment completion will need to be addressed to ensure program efficacy.
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Affiliation(s)
- Manish Pareek
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK. .,Department of Infection and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK.
| | - Christina Greenaway
- Division of Infectious Diseases and Department of Clinical Epidemiology, Jewish General Hospital, McGill University, Montreal, Canada
| | - Teymur Noori
- European Centre for Disease Prevention and Control, Solna, Sweden
| | - Jose Munoz
- Barcelona Institute for Global Health, Barcelona, Spain
| | - Dominik Zenner
- Centre for Infectious Disease Surveillance and Control, Public Health England, London, UK.,Centre for Infectious Disease Epidemiology, University College London, London, UK
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30
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Chindelevitch L, Menzies NA, Pretorius C, Stover J, Salomon JA, Cohen T. Evaluating the potential impact of enhancing HIV treatment and tuberculosis control programmes on the burden of tuberculosis. J R Soc Interface 2016; 12:rsif.2015.0146. [PMID: 25878131 PMCID: PMC4424692 DOI: 10.1098/rsif.2015.0146] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
HIV has fuelled increasing tuberculosis (TB) incidence in sub-Saharan Africa. Better control of TB in this region may be achieved directly through TB programme improvements and indirectly through expanded use of antiretroviral therapy (ART) among those with HIV. We used a mathematical model of TB and HIV in South Africa to examine the potential epidemiological impact in scenarios involving improvements in three dimensions of TB programmes: coverage, diagnosis and treatment effectiveness, as well as expanded ART use through broadened eligibility. We projected the effect of alternative scenarios on TB prevalence, incidence and TB-related mortality over 20 years. Of the three dimensions of TB programme improvement, expanding coverage would produce the greatest reduction in TB burden. Compared with current performance, combined TB programme improvements were projected to decrease TB incidence by 30% over 5 years and 46% over 20 years, and decrease TB-related mortality by 45% over 5 years and 69% over 20 years. Expanded ART eligibility was projected to decrease TB incidence by 22% over 5 years and 45% over 20 years, and TB-related mortality by 22% over 5 years and 50% over 20 years. We found that over a 20-year horizon, TB-specific and HIV-specific programme changes contribute equally to incidence reductions, whereas the TB-specific changes produce a majority of the mortality benefits. An aggressive expansion of ART alongside traditional TB-specific control measures has the potential to greatly reduce TB burden, with the different elements of a combined approach having a synergistic effect in reducing long-term TB incidence and mortality.
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Affiliation(s)
- Leonid Chindelevitch
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Nicolas A Menzies
- Center for Health Decision Science, Harvard T. H. Chan School of Public Health, Boston, MA, USA Department of Global Health and Population, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | | | | | - Joshua A Salomon
- Center for Health Decision Science, Harvard T. H. Chan School of Public Health, Boston, MA, USA Department of Global Health and Population, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
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31
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Kunkel A, Colijn C, Lipsitch M, Cohen T. How could preventive therapy affect the prevalence of drug resistance? Causes and consequences. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140306. [PMID: 25918446 PMCID: PMC4424438 DOI: 10.1098/rstb.2014.0306] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Various forms of preventive and prophylactic antimicrobial therapies have been proposed to combat HIV (e.g. pre-exposure prophylaxis), tuberculosis (e.g. isoniazid preventive therapy) and malaria (e.g. intermittent preventive treatment). However, the potential population-level effects of preventative therapy (PT) on the prevalence of drug resistance are not well understood. PT can directly affect the rate at which resistance is acquired among those receiving PT. It can also indirectly affect resistance by altering the rate at which resistance is acquired through treatment for active disease and by modifying the level of competition between transmission of drug-resistant and drug-sensitive pathogens. We propose a general mathematical model to explore the ways in which PT can affect the long-term prevalence of drug resistance. Depending on the relative contributions of these three mechanisms, we find that increasing the level of coverage of PT may result in increases, decreases or non-monotonic changes in the overall prevalence of drug resistance. These results demonstrate the complexity of the relationship between PT and drug resistance in the population. Care should be taken when predicting population-level changes in drug resistance from small pilot studies of PT or estimates based solely on its direct effects.
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Affiliation(s)
- Amber Kunkel
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA
| | - Caroline Colijn
- Department of Mathematics, Imperial College, London SW7 2AZ, UK
| | - Marc Lipsitch
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA
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32
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Assessment of the patient, health system, and population effects of Xpert MTB/RIF and alternative diagnostics for tuberculosis in Tanzania: an integrated modelling approach. LANCET GLOBAL HEALTH 2015; 2:e581-91. [PMID: 25304634 DOI: 10.1016/s2214-109x(14)70291-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Several promising new diagnostic methods and algorithms for tuberculosis have been endorsed by WHO. National tuberculosis programmes now face the decision on which methods to implement and where to place them in the diagnostic algorithm. METHODS We used an integrated model to assess the effects of different algorithms of Xpert MTB/RIF and light-emitting diode (LED) fluorescence microscopy in Tanzania. To understand the effects of new diagnostics from the patient, health system, and population perspective, the model incorporated and linked a detailed operational component and a transmission component. The model was designed to represent the operational and epidemiological context of Tanzania and was used to compare the effects and cost-effectiveness of different diagnostic options. FINDINGS Among the diagnostic options considered, we identified three strategies as cost effective in Tanzania. Full scale-up of Xpert would have the greatest population-level effect with the highest incremental cost: 346 000 disability-adjusted life-years (DALYs) averted with an additional cost of US$36·9 million over 10 years. The incremental cost-effectiveness ratio (ICER) of Xpert scale-up ($169 per DALY averted, 95% credible interval [CrI] 104-265) is below the willingness-to-pay threshold ($599) for Tanzania. Same-day LED fluorescence microscopy is the next most effective strategy with an ICER of $45 (95% CrI 25-74), followed by LED fluorescence microscopy with an ICER of $29 (6-59). Compared with same-day LED fluorescence microscopy and Xpert full rollout, targeted use of Xpert in presumptive tuberculosis cases with HIV infection, either as an initial diagnostic test or as a follow-on test to microscopy, would produce DALY gains at a higher incremental cost and therefore is dominated in the context of Tanzania. INTERPRETATION For Tanzania, this integrated modelling approach predicts that full rollout of Xpert is a cost-effective option for tuberculosis diagnosis and has the potential to substantially reduce the national tuberculosis burden. It also estimates the substantial level of funding that will need to be mobilised to translate this into clinical practice. This approach could be adapted and replicated in other developing countries to inform rational health policy formulation.
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Makoni A, Chemhuru M, Tshimanga M, Gombe NT, Mungati M, Bangure D. Evaluation of the isoniazid preventive therapy (IPT) program in Shurugwi District, Midlands Province, Zimbabwe, January 2013 to August 2014. BMC Res Notes 2015; 8:476. [PMID: 26408193 PMCID: PMC4583726 DOI: 10.1186/s13104-015-1451-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/16/2015] [Indexed: 11/25/2022] Open
Abstract
Background Midlands Province started implementing the Isoniazid (INH) preventive therapy (IPT) program in January 2013. Shurugwi and Gokwe North were the piloting district hospitals. In May 2014, four more districts hospitals (Gokwe South, Gweru, Kwekwe and Zvishavane) started implementing IPT. Shurugwi District decentralized the program to its rural health facilities in January 2014. A review of the Shurugwi IPT program, 2013 data, indicated that the majority of eligible clients were not started on IPT. None out of the 400 eligible clients were started on IPT in November against the 100 % target according to the World Health Organization and the National Tuberculosis (TB) Program. We conducted a study to evaluate the IPT program in Shurugwi District from January 2013 to August 2014. Methods The logical framework approach was used to evaluate inputs, processes, outputs and outcomes of the IPT program. An interviewer administered questionnaire was used to collect data from key informants. Checklists were used to collect data from IPT program records. Results Sixteen health facilities were implementing IPT in Shurugwi District. All the facilities had TB screening tools and three did not have TB screening algorithms. The district experienced medicine stock outs in 2013. One formal training at district level and on job trainings in implementing health facilities were done. From January 2013 to August 2014, Shurugwi District screened 6794 antiretroviral (ART) clients for TB. Out of those screened, 5255 were eligible for IPT and 2831 (54 %) were started on IPT. A total of 700 clients had completed the IPT 6 month’s course by August 2014. The dropout rate due to INH toxicity and TB was 0.6 % (n = 18) and 0.3 % (n = 8) respectively. Fifty-three advocacy and community sensitization meetings were done. The program had no Information Education and Communication (IEC) materials. Conclusion The IPT program in Shurugwi District achieved half its target. This could be due to inadequate formally trained staff, lack of IEC materials, inadequate advocacy and community sensitization, non-availability of the INH 300 mg single dose and inadequate INH 100 mg dose tablets in 2013. To improve the IPT program, there is need for routine advocacy, communication and social mobilization.
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Affiliation(s)
- Annamercy Makoni
- Department of Community Medicine, University of Zimbabwe, Office 3-66 Kaguvi Building, Cnr 4th/Central Avenue, Harare, Zimbabwe.
| | | | - Mufuta Tshimanga
- Department of Community Medicine, University of Zimbabwe, Office 3-66 Kaguvi Building, Cnr 4th/Central Avenue, Harare, Zimbabwe.
| | - Notion Tafara Gombe
- Department of Community Medicine, University of Zimbabwe, Office 3-66 Kaguvi Building, Cnr 4th/Central Avenue, Harare, Zimbabwe.
| | - More Mungati
- Department of Community Medicine, University of Zimbabwe, Office 3-66 Kaguvi Building, Cnr 4th/Central Avenue, Harare, Zimbabwe.
| | - Donewell Bangure
- Department of Community Medicine, University of Zimbabwe, Office 3-66 Kaguvi Building, Cnr 4th/Central Avenue, Harare, Zimbabwe.
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Colijn C, Cohen T. How competition governs whether moderate or aggressive treatment minimizes antibiotic resistance. eLife 2015; 4. [PMID: 26393685 PMCID: PMC4641510 DOI: 10.7554/elife.10559] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 09/18/2015] [Indexed: 11/16/2022] Open
Abstract
Understanding how our use of antimicrobial drugs shapes future levels of drug resistance is crucial. Recently, there has been debate over whether an aggressive (i.e., high dose) or more moderate (i.e., lower dose) treatment of individuals will most limit the emergence and spread of resistant bacteria. In this study, we demonstrate how one can understand and resolve these apparently contradictory conclusions. We show that a key determinant of which treatment strategy will perform best at the individual level is the extent of effective competition between resistant and sensitive pathogens within a host. We extend our analysis to the community level, exploring the spectrum between strict inter-strain competition and strain independence. From this perspective as well, we find that the magnitude of effective competition between resistant and sensitive strains determines whether an aggressive approach or moderate approach minimizes the burden of resistance in the population. DOI:http://dx.doi.org/10.7554/eLife.10559.001 Antibiotics are chemical compounds used to treat bacterial infections. The discovery of antibiotics, starting with penicillin in 1929, revolutionized medicine, making it possible to cure or prevent life-threatening infections such as tetanus and pneumonia. However, many bacteria have become resistant to one or more antibiotics and so can no longer be killed by these drugs. The emergence of antibiotic resistance reflects an evolutionary process that occurs during antibiotic treatment. While the antibiotic will kill most bacteria, some bacteria may naturally have a feature or genetic mutation that allows them to survive in the presence of the antibiotic. These bacteria then reproduce and pass on their resistant traits, eventually leading to the emergence of a new antibiotic-resistant strain of bacteria. Once a resistant strain exists it may be able to spread from one person to another. There is conflicting evidence about how best to prevent antibiotic-resistant bacteria from evolving and spreading. The results of some experiments suggest that treating bacteria with large doses of antibiotics early in an infection is the most effective way to optimize treatment and minimize the risk of an antibiotic-resistant strain developing. However, other studies suggest that exposing bacteria to high levels of antibiotics more efficiently selects for resistance; in this case a more moderate approach should be used when treating bacterial infections. Here, Colijn and Cohen present a mathematical model that suggests that the natural competition between the antibiotic-resistant and antibiotic-sensitive strains of bacteria influence which treatment strategy should be taken. Strains were modeled both within individual hosts and spreading in a community of individuals. In the models, aggressive antibiotic treatment is most effective (in that it minimizes antibiotic resistance) when the antibiotic-resistant strain either does not experience strong competition from the non-resistant strains of bacteria or is not fit enough to be a good competitor. However, a more moderate treatment is appropriate when the two strains are competing and the antibiotic-resistant strain is a fit competitor. Competition may mean that moderate treatment is best to avoid resistance at the community level, even in situations when aggressive treatment is likely best for individuals. Two important future challenges are to better understand the diversity of strains in bacterial infections, and to develop tools to measure to what extent strains are effectively competing with each other. DOI:http://dx.doi.org/10.7554/eLife.10559.002
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Affiliation(s)
- Caroline Colijn
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Ted Cohen
- School of Public Health, Yale University, New Haven, United States
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Cohen KA, Abeel T, Manson McGuire A, Desjardins CA, Munsamy V, Shea TP, Walker BJ, Bantubani N, Almeida DV, Alvarado L, Chapman SB, Mvelase NR, Duffy EY, Fitzgerald MG, Govender P, Gujja S, Hamilton S, Howarth C, Larimer JD, Maharaj K, Pearson MD, Priest ME, Zeng Q, Padayatchi N, Grosset J, Young SK, Wortman J, Mlisana KP, O'Donnell MR, Birren BW, Bishai WR, Pym AS, Earl AM. Evolution of Extensively Drug-Resistant Tuberculosis over Four Decades: Whole Genome Sequencing and Dating Analysis of Mycobacterium tuberculosis Isolates from KwaZulu-Natal. PLoS Med 2015; 12:e1001880. [PMID: 26418737 PMCID: PMC4587932 DOI: 10.1371/journal.pmed.1001880] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/20/2015] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The continued advance of antibiotic resistance threatens the treatment and control of many infectious diseases. This is exemplified by the largest global outbreak of extensively drug-resistant (XDR) tuberculosis (TB) identified in Tugela Ferry, KwaZulu-Natal, South Africa, in 2005 that continues today. It is unclear whether the emergence of XDR-TB in KwaZulu-Natal was due to recent inadequacies in TB control in conjunction with HIV or other factors. Understanding the origins of drug resistance in this fatal outbreak of XDR will inform the control and prevention of drug-resistant TB in other settings. In this study, we used whole genome sequencing and dating analysis to determine if XDR-TB had emerged recently or had ancient antecedents. METHODS AND FINDINGS We performed whole genome sequencing and drug susceptibility testing on 337 clinical isolates of Mycobacterium tuberculosis collected in KwaZulu-Natal from 2008 to 2013, in addition to three historical isolates, collected from patients in the same province and including an isolate from the 2005 Tugela Ferry XDR outbreak, a multidrug-resistant (MDR) isolate from 1994, and a pansusceptible isolate from 1995. We utilized an array of whole genome comparative techniques to assess the relatedness among strains, to establish the order of acquisition of drug resistance mutations, including the timing of acquisitions leading to XDR-TB in the LAM4 spoligotype, and to calculate the number of independent evolutionary emergences of MDR and XDR. Our sequencing and analysis revealed a 50-member clone of XDR M. tuberculosis that was highly related to the Tugela Ferry XDR outbreak strain. We estimated that mutations conferring isoniazid and streptomycin resistance in this clone were acquired 50 y prior to the Tugela Ferry outbreak (katG S315T [isoniazid]; gidB 130 bp deletion [streptomycin]; 1957 [95% highest posterior density (HPD): 1937-1971]), with the subsequent emergence of MDR and XDR occurring 20 y (rpoB L452P [rifampicin]; pncA 1 bp insertion [pyrazinamide]; 1984 [95% HPD: 1974-1992]) and 10 y (rpoB D435G [rifampicin]; rrs 1400 [kanamycin]; gyrA A90V [ofloxacin]; 1995 [95% HPD: 1988-1999]) prior to the outbreak, respectively. We observed frequent de novo evolution of MDR and XDR, with 56 and nine independent evolutionary events, respectively. Isoniazid resistance evolved before rifampicin resistance 46 times, whereas rifampicin resistance evolved prior to isoniazid only twice. We identified additional putative compensatory mutations to rifampicin in this dataset. One major limitation of this study is that the conclusions with respect to ordering and timing of acquisition of mutations may not represent universal patterns of drug resistance emergence in other areas of the globe. CONCLUSIONS In the first whole genome-based analysis of the emergence of drug resistance among clinical isolates of M. tuberculosis, we show that the ancestral precursor of the LAM4 XDR outbreak strain in Tugela Ferry gained mutations to first-line drugs at the beginning of the antibiotic era. Subsequent accumulation of stepwise resistance mutations, occurring over decades and prior to the explosion of HIV in this region, yielded MDR and XDR, permitting the emergence of compensatory mutations. Our results suggest that drug-resistant strains circulating today reflect not only vulnerabilities of current TB control efforts but also those that date back 50 y. In drug-resistant TB, isoniazid resistance was overwhelmingly the initial resistance mutation to be acquired, which would not be detected by current rapid molecular diagnostics employed in South Africa that assess only rifampicin resistance.
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Affiliation(s)
- Keira A. Cohen
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
| | - Thomas Abeel
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
| | | | | | - Vanisha Munsamy
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
| | - Terrance P. Shea
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Bruce J. Walker
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | | | - Deepak V. Almeida
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
- Center for Tuberculosis Research, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Lucia Alvarado
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Sinéad B. Chapman
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Nomonde R. Mvelase
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- National Health Laboratory Service, Durban, South Africa
| | - Eamon Y. Duffy
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
| | - Michael G. Fitzgerald
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Pamla Govender
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
| | - Sharvari Gujja
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Susanna Hamilton
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Clinton Howarth
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Jeffrey D. Larimer
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Kashmeel Maharaj
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
| | - Matthew D. Pearson
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Margaret E. Priest
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Qiandong Zeng
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Nesri Padayatchi
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Jacques Grosset
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
- Center for Tuberculosis Research, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Sarah K. Young
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Jennifer Wortman
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Koleka P. Mlisana
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- National Health Laboratory Service, Durban, South Africa
| | - Max R. O'Donnell
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University College of Physicians and Surgeons, New York, United States of America
- Department of Epidemiology, Columbia Mailman School of Public Health, New York, United States of America
| | - Bruce W. Birren
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - William R. Bishai
- Center for Tuberculosis Research, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Alexander S. Pym
- KwaZulu-Natal Research Institute for TB and HIV (K-RITH), Durban, South Africa
- * E-mail: (ASP); (AME)
| | - Ashlee M. Earl
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- * E-mail: (ASP); (AME)
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Gilbert JA, Long EF, Brooks RP, Friedland GH, Moll AP, Townsend JP, Galvani AP, Shenoi SV. Integrating Community-Based Interventions to Reverse the Convergent TB/HIV Epidemics in Rural South Africa. PLoS One 2015; 10:e0126267. [PMID: 25938501 PMCID: PMC4418809 DOI: 10.1371/journal.pone.0126267] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 03/31/2015] [Indexed: 12/22/2022] Open
Abstract
The WHO recommends integrating interventions to address the devastating TB/HIV co-epidemics in South Africa, yet integration has been poorly implemented and TB/HIV control efforts need strengthening. Identifying infected individuals is particularly difficult in rural settings. We used mathematical modeling to predict the impact of community-based, integrated TB/HIV case finding and additional control strategies on South Africa’s TB/HIV epidemics. We developed a model incorporating TB and HIV transmission to evaluate the effectiveness of integrating TB and HIV interventions in rural South Africa over 10 years. We modeled the impact of a novel screening program that integrates case finding for TB and HIV in the community, comparing it to status quo and recommended TB/HIV control strategies, including GeneXpert, MDR-TB treatment decentralization, improved first-line TB treatment cure rate, isoniazid preventive therapy, and expanded ART. Combining recommended interventions averted 27% of expected TB cases (95% CI 18–40%) 18% HIV (95% CI 13–24%), 60% MDR-TB (95% CI 34–83%), 69% XDR-TB (95% CI 34–90%), and 16% TB/HIV deaths (95% CI 12–29). Supplementing these interventions with annual community-based TB/HIV case finding averted a further 17% of TB cases (44% total; 95% CI 31–56%), 5% HIV (23% total; 95% CI 17–29%), 8% MDR-TB (68% total; 95% CI 40–88%), 4% XDR-TB (73% total; 95% CI 38–91%), and 8% TB/HIV deaths (24% total; 95% CI 16–39%). In addition to increasing screening frequency, we found that improving TB symptom questionnaire sensitivity, second-line TB treatment delays, default before initiating TB treatment or ART, and second-line TB drug efficacy were significantly associated with even greater reductions in TB and HIV cases. TB/HIV epidemics in South Africa were most effectively curtailed by simultaneously implementing interventions that integrated community-based TB/HIV control strategies and targeted drug-resistant TB. Strengthening existing TB and HIV treatment programs is needed to further reduce disease incidence.
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Affiliation(s)
- Jennifer A Gilbert
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America; Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, United States of America
| | - Elisa F Long
- Anderson School of Management, University of California Los Angeles, Los Angeles, CA, United States of America
| | - Ralph P Brooks
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, CT, United States of America
| | - Gerald H Friedland
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America; Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, CT, United States of America
| | - Anthony P Moll
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, CT, United States of America; Church of Scotland Hospital, Tugela Ferry, KwaZulu-Natal, South Africa
| | - Jeffrey P Townsend
- Department of Biostatistics, Yale University, New Haven, CT, United States of America; Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States of America; Program in Computational Biology and Informatics, Yale University, New Haven, CT, United States of America
| | - Alison P Galvani
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America; Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, United States of America; Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States of America; Program in Computational Biology and Informatics, Yale University, New Haven, CT, United States of America
| | - Sheela V Shenoi
- Department of Medicine, Section of Infectious Diseases, AIDS Program, Yale University School of Medicine, New Haven, CT, United States of America
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Pan SC, Ku CC, Kao D, Ezzati M, Fang CT, Lin HH. Effect of diabetes on tuberculosis control in 13 countries with high tuberculosis: a modelling study. Lancet Diabetes Endocrinol 2015; 3:323-30. [PMID: 25754415 DOI: 10.1016/s2213-8587(15)00042-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Diabetes increases the risk of tuberculosis incidence and the risk of adverse treatment outcomes in patients with tuberculosis. Because prevalence of diabetes is increasing in low-income and middle-income countries where the burden of tuberculosis is high, prevention of diabetes carries the potential to improve tuberculosis control worldwide. METHODS We used dynamic tuberculosis transmission models to analyse the potential effect of diabetes on tuberculosis epidemiology in 13 countries with high tuberculosis burden. We used data for previous diabetes prevalence in each country and constructed scenarios to represent the potential ranges of future diabetes prevalence. The country-specific model was calibrated to the estimated trend of tuberculosis incidence. We estimated the tuberculosis burden that can be reduced by alternative scenarios of diabetes prevention. FINDINGS If the prevalence of diabetes continues to rise as it has been in the past decade in the 13 countries (base case scenario), by 2035, the cumulative reduction in tuberculosis incidence would be 8·8% (95% credible interval [CrI] 4·0-15·8) and mortality would be 34·0% (30·3-39·6). Lowering the prevalence of diabetes by an absolute level of 6·6-13·8% could accelerate the decline of tuberculosis incidence by an absolute level of 11·5-25·2% and tuberculosis mortality by 8·7-19·4%. Compared with the base case scenario, stopping the rise of diabetes would avoid 6·0 million (95% CrI 5·1-6·9) incident cases and 1·1 million (1·0-1·3) tuberculosis deaths in 13 countries during 20 years. If interventions reduce diabetes incidence by 35% by 2025, 7·8 million (6·7-9·0) tuberculosis cases and 1·5 million (1·3-1·7) tuberculosis deaths could be averted by 2035. INTERPRETATION The diabetes epidemic could substantially affect tuberculosis epidemiology in high burden countries. The communicable disease and non-communicable disease sectors need to move beyond conventional boundaries and link with each other to form a joint response to diabetes and tuberculosis. FUNDING Taiwan National Science Council.
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Affiliation(s)
- Sung-Ching Pan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Chu-Chang Ku
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Diana Kao
- Department of Epidemiology and Biostatistics, University of British Columbia, Vancouver, Canada
| | - Majid Ezzati
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, UK
| | - Chi-Tai Fang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
| | - Hsien-Ho Lin
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
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Denysiuk R, Silva CJ, Torres DFM. Multiobjective approach to optimal control for a tuberculosis model. OPTIMIZATION METHODS & SOFTWARE 2015. [DOI: 10.1080/10556788.2014.994704] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Houben RMGJ, Dowdy DW, Vassall A, Cohen T, Nicol MP, Granich RM, Shea JE, Eckhoff P, Dye C, Kimerling ME, White RG. How can mathematical models advance tuberculosis control in high HIV prevalence settings? Int J Tuberc Lung Dis 2015; 18:509-14. [PMID: 24903784 PMCID: PMC4436821 DOI: 10.5588/ijtld.13.0773] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Existing approaches to tuberculosis (TB) control have been no more than partially successful in areas with high human immunodeficiency virus (HIV) prevalence. In the context of increasingly constrained resources, mathematical modelling can augment understanding and support policy for implementing those strategies that are most likely to bring public health and economic benefits. In this paper, we present an overview of past and recent contributions of TB modelling in this key area, and suggest a way forward through a modelling research agenda that supports a more effective response to the TB-HIV epidemic, based on expert discussions at a meeting convened by the TB Modelling and Analysis Consortium. The research agenda identified high-priority areas for future modelling efforts, including 1) the difficult diagnosis and high mortality of TB-HIV; 2) the high risk of disease progression; 3) TB health systems in high HIV prevalence settings; 4) uncertainty in the natural progression of TB-HIV; and 5) combined interventions for TB-HIV. Efficient and rapid progress towards completion of this modelling agenda will require co-ordination between the modelling community and key stakeholders, including advocates, health policy makers, donors and national or regional finance officials. A continuing dialogue will ensure that new results are effectively communicated and new policy-relevant questions are addressed swiftly.
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Affiliation(s)
- R M G J Houben
- TB Modelling Group, TB Centre, and Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, UK
| | - D W Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - A Vassall
- Department of Global Health and Development, LSHTM, London, UK
| | - T Cohen
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
| | - M P Nicol
- Division of Medical Microbiology and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town and National Health Laboratory Service, South Africa
| | - R M Granich
- Joint United Nations Programme on HIV/AIDS, World Health Organization (WHO), Geneva, Switzerland
| | - J E Shea
- Oxford-Emergent Tuberculosis Consortium, Wokingham, UK
| | - P Eckhoff
- Intellectual Ventures Laboratory, Bellevue, Washington, USA
| | - C Dye
- HIV, TB Malaria and Neglected Tropical Diseases Cluster, WHO, Geneva, Switzerland
| | - M E Kimerling
- Bill and Melinda Gates Foundation, Seattle, Washington, USA
| | - R G White
- TB Modelling Group, TB Centre, and Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine (LSHTM), London, UK
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Impact of isoniazid preventive therapy for HIV-infected adults in Rio de Janeiro, Brazil: an epidemiological model. J Acquir Immune Defic Syndr 2014; 66:552-8. [PMID: 24853308 DOI: 10.1097/qai.0000000000000219] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The potential epidemiological impact of isoniazid preventive therapy (IPT), delivered at levels that could be feasibly scaled up among people living with HIV (PLHIV) in modern, moderate-burden settings, remains uncertain. METHODS We used routine surveillance and implementation data from a cluster-randomized trial of IPT among HIV-infected clinic patients with good access to antiretroviral therapy in Rio de Janeiro, Brazil, to populate a parsimonious transmission model of tuberculosis (TB)/HIV. We modeled IPT delivery as a constant process capturing a proportion of the eligible population every year. We projected feasible reductions in TB incidence and mortality in the general population and among PLHIV specifically at the end of 5 years after implementing an IPT program. RESULTS Data on time to IPT fit an exponential curve well, suggesting that IPT was delivered at a rate covering 20% (95% confidence interval: 16% to 24%) of the 2500 eligible individuals each year. By the end of year 5 after modeled program rollout, IPT had reduced TB incidence by 3.0% [95% uncertainty range (UR): 1.6% to 7.2%] in the general population and by 15.6% (95% UR: 15.5% to 36.5%) among PLHIV. Corresponding reductions in TB mortality were 4.0% (95% UR: 2.2% to 10.3%) and 14.3% (14.6% to 33.7%). Results were robust to wide variations in parameter values on sensitivity analysis. CONCLUSIONS TB screening and IPT delivery can substantially reduce TB incidence and mortality among PLHIV in urban, moderate-burden settings. In such settings, IPT can be an important component of a multi-faceted strategy to feasibly reduce the burden of TB in PLHIV.
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Dowdy DW, Dye C, Cohen T. Data needs for evidence-based decisions: a tuberculosis modeler's 'wish list'. Int J Tuberc Lung Dis 2014; 17:866-77. [PMID: 23743307 DOI: 10.5588/ijtld.12.0573] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Infectious disease models are important tools for understanding epidemiology and supporting policy decisions for disease control. In the case of tuberculosis (TB), such models have informed our understanding and control strategies for over 40 years, but the primary assumptions of these models--and their most urgent data needs--remain obscure to many TB researchers and control officers. The structure and parameter values of TB models are informed by observational studies and experiments, but the evidence base in support of these models remains incomplete. Speaking from the perspective of infectious disease modelers addressing the broader TB research and control communities, we describe the basic structure common to most TB models and present a 'wish list' that would improve the evidence foundation upon which these models are built. As a comprehensive TB research agenda is formulated, we argue that the data needs of infectious disease models--our primary long-term decision-making tools--should figure prominently.
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Affiliation(s)
- D W Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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42
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Denkinger CM, Pai M, Dowdy DW. Do we need to detect isoniazid resistance in addition to rifampicin resistance in diagnostic tests for tuberculosis? PLoS One 2014; 9:e84197. [PMID: 24404155 PMCID: PMC3880287 DOI: 10.1371/journal.pone.0084197] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 11/12/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Multidrug-resistant tuberculosis (MDR-TB) is resistant to both rifampicin (RIF) and isoniazid (INH). Whereas many TB diagnostics detect RIF-resistance, few detect INH-monoresistance, which is common and may increase risk of acquired MDR-TB. Whether inclusion of INH-resistance in a first-line rapid test for TB would have an important impact on MDR-TB rates remains uncertain. METHODS WE DEVELOPED A TRANSMISSION MODEL TO EVALUATE THREE TESTS IN A POPULATION SIMILAR TO THAT OF INDIA: a rapid molecular test for TB, the same test plus RIF-resistance detection ("TB+RIF"), and detection of RIF and INH-resistance ("TB+RIF/INH"). Our primary outcome was the prevalence of INH-resistant and MDR-TB at ten years. RESULTS Compared to the TB test alone and assuming treatment of all diagnosed MDR cases, the TB+RIF test reduced the prevalence of MDR-TB among all TB cases from 5.5% to 3.8% (30.6% reduction, 95% uncertainty range, UR: 17-54%). Despite using liberal assumptions about the impact of INH-monoresistance on treatment outcomes and MDR-TB acquisition, expansion from TB+RIF to TB+RIF/INH lowered this prevalence only from 3.8% to 3.6% further (4% reduction, 95% UR: 3-7%) and INH-monoresistant TB from 15.8% to 15.1% (4% reduction, 95% UR: (-8)-19%). CONCLUSION When added to a rapid test for TB plus RIF-resistance, detection of INH-resistance has minimal impact on transmission of TB, MDR-TB, and INH-monoresistant TB.
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Affiliation(s)
- Claudia M. Denkinger
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- McGill International TB Centre & Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Madhukar Pai
- McGill International TB Centre & Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Montreal, Quebec, Canada
| | - David W. Dowdy
- Department of Epidemiology, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Center for Tuberculosis Research, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
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Mathematical modeling of the HIV/Kaposi's sarcoma coinfection dynamics in areas of high HIV prevalence. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:753424. [PMID: 24348744 PMCID: PMC3855956 DOI: 10.1155/2013/753424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 08/29/2013] [Accepted: 09/12/2013] [Indexed: 11/20/2022]
Abstract
We formulate a deterministic system of ordinary differential equations to quantify HAART treatment levels for patients co-infected with HIV and Kaposi's Sarcoma in a high HIV prevalence setting. A qualitative stability analysis of the equilibrium states is carried out and we find that the disease-free equilibrium is globally attracting whenever the reproductive number ℛ
k < 1. A unique endemic equilibrium exists and is locally stable whenever ℛ
k > 1. Therefore, reducing ℛ
k to below unity should be the goal for disease eradication. Provision of HAART is shown to provide dual benefit of reducing HIV spread and the risk of acquiring another fatal disease for HIV/AIDS patients. By providing treatment to 10% of the HIV population, about 87% of the AIDS population acquire protection against coinfection with HIV and Kaposi's Sarcoma (KS). Most sub-Sahara African countries already have programmes in place to screen HIV. Our recommendation is that these programmes should be expanded to include testing for HHV-8 and KS counseling.
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44
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Spicknall IH, Foxman B, Marrs CF, Eisenberg JNS. A modeling framework for the evolution and spread of antibiotic resistance: literature review and model categorization. Am J Epidemiol 2013; 178:508-20. [PMID: 23660797 PMCID: PMC3736756 DOI: 10.1093/aje/kwt017] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antibiotic-resistant infections complicate treatment and increase morbidity and mortality. Mathematical modeling has played an integral role in improving our understanding of antibiotic resistance. In these models, parameter sensitivity is often assessed, while model structure sensitivity is not. To examine the implications of this, we first reviewed the literature on antibiotic-resistance modeling published between 1993 and 2011. We then classified each article's model structure into one or more of 6 categories based on the assumptions made in those articles regarding within-host and population-level competition between antibiotic-sensitive and antibiotic-resistant strains. Each model category has different dynamic implications with respect to how antibiotic use affects resistance prevalence, and therefore each may produce different conclusions about optimal treatment protocols that minimize resistance. Thus, even if all parameter values are correctly estimated, inferences may be incorrect because of the incorrect selection of model structure. Our framework provides insight into model selection.
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Affiliation(s)
- Ian H Spicknall
- Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA.
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45
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Silva CJ, Torres DFM. Optimal control for a tuberculosis model with reinfection and post-exposure interventions. Math Biosci 2013; 244:154-64. [PMID: 23707607 DOI: 10.1016/j.mbs.2013.05.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 02/05/2023]
Affiliation(s)
- Cristiana J Silva
- CIDMA - Center for Research and Development in Mathematics and Applications, Department of Mathematics, University of Aveiro, 3810-193 Aveiro, Portugal.
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46
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Mills HL, Cohen T, Colijn C. Community-wide isoniazid preventive therapy drives drug-resistant tuberculosis: a model-based analysis. Sci Transl Med 2013; 5:180ra49. [PMID: 23576815 PMCID: PMC3714172 DOI: 10.1126/scitranslmed.3005260] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Tuberculosis (TB) control is especially difficult in settings of high HIV prevalence; HIV co-infection erodes host immunity and increases risk of progression to active TB. Studies have demonstrated that a 6-month (or longer) course of monotherapy with isoniazid [isoniazid preventive therapy (IPT)] can reduce this risk. The World Health Organization endorses IPT for symptom-free individuals with HIV/TB co-infection and has recommended expanding IPT to entire communities (community-wide IPT). Although previous reviews have not found a statistically significant elevated risk of isoniazid-resistant TB among individuals previously treated with IPT, community-wide IPT programs may nonetheless generate substantial selective pressure and increase the burden of drug-resistant TB (DRTB). We developed mathematical models to identify the conditions under which community-wide IPT interventions could increase the burden of isoniazid-resistant Mycobacterium tuberculosis, even when we assumed that IPT does not select for resistance among those treated with IPT. We found that in models that included any mechanism of interstrain competition (such as partial immunity conferred by a previous M. tuberculosis infection), community-wide IPT interventions conferred an indirect benefit to drug-resistant strains through selective suppression of drug-sensitive infections. This result suggests that the absence of an observed elevation in the risk of DRTB among those receiving IPT in small-scale studies of limited duration does not imply that the selective pressure imposed by community-wide IPT will not be substantial. Community-wide IPT may play an important role in TB control in these settings, and its rollout should be accompanied by interventions to detect and treat drug-resistant disease.
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Affiliation(s)
- Harriet L Mills
- Bristol Centre for Complexity Sciences, University of Bristol, Bristol BS8 1TR, UK
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47
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Mixed-strain mycobacterium tuberculosis infections and the implications for tuberculosis treatment and control. Clin Microbiol Rev 2013; 25:708-19. [PMID: 23034327 DOI: 10.1128/cmr.00021-12] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous studies have reported that individuals can simultaneously harbor multiple distinct strains of Mycobacterium tuberculosis. To date, there has been limited discussion of the consequences for the individual or the epidemiological importance of mixed infections. Here, we review studies that documented mixed infections, highlight challenges associated with the detection of mixed infections, and discuss possible implications of mixed infections for the diagnosis and treatment of patients and for the community impact of tuberculosis control strategies. We conclude by highlighting questions that should be resolved in order to improve our understanding of the importance of mixed-strain M. tuberculosis infections.
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Ben-Haim Y, Dacso CC, Zetola NM. Info-gap management of public health Policy for TB with HIV-prevalence and epidemiological uncertainty. BMC Public Health 2012; 12:1091. [PMID: 23249291 PMCID: PMC3583706 DOI: 10.1186/1471-2458-12-1091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/04/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Formulation and evaluation of public health policy commonly employs science-based mathematical models. For instance, epidemiological dynamics of TB is dominated, in general, by flow between actively and latently infected populations. Thus modelling is central in planning public health intervention. However, models are highly uncertain because they are based on observations that are geographically and temporally distinct from the population to which they are applied. AIMS We aim to demonstrate the advantages of info-gap theory, a non-probabilistic approach to severe uncertainty when worst cases cannot be reliably identified and probability distributions are unreliable or unavailable. Info-gap is applied here to mathematical modelling of epidemics and analysis of public health decision-making. METHODS Applying info-gap robustness analysis to tuberculosis/HIV (TB/HIV) epidemics, we illustrate the critical role of incorporating uncertainty in formulating recommendations for interventions. Robustness is assessed as the magnitude of uncertainty that can be tolerated by a given intervention. We illustrate the methodology by exploring interventions that alter the rates of diagnosis, cure, relapse and HIV infection. RESULTS We demonstrate several policy implications. Equivalence among alternative rates of diagnosis and relapse are identified. The impact of initial TB and HIV prevalence on the robustness to uncertainty is quantified. In some configurations, increased aggressiveness of intervention improves the predicted outcome but also reduces the robustness to uncertainty. Similarly, predicted outcomes may be better at larger target times, but may also be more vulnerable to model error. CONCLUSIONS The info-gap framework is useful for managing model uncertainty and is attractive when uncertainties on model parameters are extreme. When a public health model underlies guidelines, info-gap decision theory provides valuable insight into the confidence of achieving agreed-upon goals.
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Affiliation(s)
- Yakov Ben-Haim
- Yitzhak Moda’i Chair in Technology and Economics, Technion--Israel Institute of Technology, Haifa 32000, Israel
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Menzies NA, Cohen T, Lin HH, Murray M, Salomon JA. Population health impact and cost-effectiveness of tuberculosis diagnosis with Xpert MTB/RIF: a dynamic simulation and economic evaluation. PLoS Med 2012; 9:e1001347. [PMID: 23185139 PMCID: PMC3502465 DOI: 10.1371/journal.pmed.1001347] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 10/12/2012] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND The Xpert MTB/RIF test enables rapid detection of tuberculosis (TB) and rifampicin resistance. The World Health Organization recommends Xpert for initial diagnosis in individuals suspected of having multidrug-resistant TB (MDR-TB) or HIV-associated TB, and many countries are moving quickly toward adopting Xpert. As roll-out proceeds, it is essential to understand the potential health impact and cost-effectiveness of diagnostic strategies based on Xpert. METHODS AND FINDINGS We evaluated potential health and economic consequences of implementing Xpert in five southern African countries--Botswana, Lesotho, Namibia, South Africa, and Swaziland--where drug resistance and TB-HIV coinfection are prevalent. Using a calibrated, dynamic mathematical model, we compared the status quo diagnostic algorithm, emphasizing sputum smear, against an algorithm incorporating Xpert for initial diagnosis. Results were projected over 10- and 20-y time periods starting from 2012. Compared to status quo, implementation of Xpert would avert 132,000 (95% CI: 55,000-284,000) TB cases and 182,000 (97,000-302,000) TB deaths in southern Africa over the 10 y following introduction, and would reduce prevalence by 28% (14%-40%) by 2022, with more modest reductions in incidence. Health system costs are projected to increase substantially with Xpert, by US$460 million (294-699 million) over 10 y. Antiretroviral therapy for HIV represents a substantial fraction of these additional costs, because of improved survival in TB/HIV-infected populations through better TB case-finding and treatment. Costs for treating MDR-TB are also expected to rise significantly with Xpert scale-up. Relative to status quo, Xpert has an estimated cost-effectiveness of US$959 (633-1,485) per disability-adjusted life-year averted over 10 y. Across countries, cost-effectiveness ratios ranged from US$792 (482-1,785) in Swaziland to US$1,257 (767-2,276) in Botswana. Assessing outcomes over a 10-y period focuses on the near-term consequences of Xpert adoption, but the cost-effectiveness results are conservative, with cost-effectiveness ratios assessed over a 20-y time horizon approximately 20% lower than the 10-y values. CONCLUSIONS Introduction of Xpert could substantially change TB morbidity and mortality through improved case-finding and treatment, with more limited impact on long-term transmission dynamics. Despite extant uncertainty about TB natural history and intervention impact in southern Africa, adoption of Xpert evidently offers reasonable value for its cost, based on conventional benchmarks for cost-effectiveness. However, the additional financial burden would be substantial, including significant increases in costs for treating HIV and MDR-TB. Given the fundamental influence of HIV on TB dynamics and intervention costs, care should be taken when interpreting the results of this analysis outside of settings with high HIV prevalence.
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Affiliation(s)
- Nicolas A Menzies
- Center for Health Decision Sciences, Harvard School of Public Health, Boston, Massachusetts, United States of America.
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50
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Johnston J, Admon A, Ibrahim A, Elwood K, Tang P, Cook V, Fitzgerald M. Long term follow-up of drug resistant and drug susceptible tuberculosis contacts in a Low incidence setting. BMC Infect Dis 2012; 12:266. [PMID: 23088397 PMCID: PMC3524765 DOI: 10.1186/1471-2334-12-266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 10/18/2012] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Studies examining the transmission of multidrug-resistant tuberculosis (MDR-TB) strains have yielded conflicting results. METHODS We examined transmission of MDR-TB strains using contact tracing data from a low incidence setting. Contacts of MDR-TB cases diagnosed in British Columbia, Canada, from 1990-2008 were identified through a provincial tuberculosis (TB) registry. Tuberculin skin test (TST) results and TB disease incident rates were determined for contacts. For comparison, TB disease incident rates and TST results were measured in close contacts of isoniazid mono-resistant (HMR-TB) and drug susceptible TB (DS-TB) cases. RESULTS Of 89 identified close contacts of MDR-TB patients, 5 patients (6%) developed TB disease and 42 (47%) were TST positive. The incidence rate of TB disease (3%, p = 0.31) and TST positivity (49%, p = 0.82) were similar in contacts of HMR-TB cases. Compared with MDR-TB contacts, DS-TB contacts had lower incidence rate of TB disease (2%, p = 0.04) and TST positivity (32%, p < 0.01). All MDR-TB contacts with culture positive TB diagnosed in follow-up were drug-susceptible; three of six HMR-TB contacts with culture positive TB were HMR-TB. Multivariate analysis demonstrated that contact with MDR-TB (adjusted OR 1.72; 95%CI 1.05-2.81) and HMR-TB (adjusted OR 1.99; 95%CI 1.48-2.67) was associated with TST positivity. In addition, adult age, male gender, BCG positivity, source case sputum smear positivity, foreign birth and fewer contacts per source case were significantly associated with TST positivity in the multivariate model. CONCLUSION Contacts of MDR-TB and HMR-TB patients in a low incidence setting show high rates of TST positivity and TB disease but low rates of drug resistance.
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Affiliation(s)
- James Johnston
- Division of Tuberculosis Control, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Andrew Admon
- Department of Internal Medicine, University of Michigan Health System, Ann Arbor, MI, 48109, USA
| | - Amir Ibrahim
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kevin Elwood
- Division of Tuberculosis Control, British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - Patrick Tang
- Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Victoria Cook
- Division of Tuberculosis Control, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Mark Fitzgerald
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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