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Buis JS, Jerene D, Gebhard A, Bakker R, Majidulla A, Kerkhoff AD, Limaye RJ, Pelzer PT. Mapping the existing body of knowledge on new and repurposed TB vaccine implementation: A scoping review. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0002885. [PMID: 39172796 PMCID: PMC11340902 DOI: 10.1371/journal.pgph.0002885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/10/2024] [Indexed: 08/24/2024]
Abstract
There is global consensus on the urgent need for a safe and effective TB vaccine for adults and adolescents to improve global TB control, and encouragingly, several promising candidates have advanced to late-stage trials. Significant gaps remain in understanding the critical factors that will facilitate the successful implementation of new and repurposed TB vaccines in low- and middle-income countries (LMICs), once available. By synthesizing the existing body of knowledge, this review offers comprehensive insights into the current state of research on implementation of these adult and adolescent vaccines. This review explores four key dimensions: (1) epidemiological impact, (2) costing, cost-effectiveness, and/or economic impact, (3) acceptability, and the (4) feasibility of implementation; this includes implementation strategies of target populations, and health system capabilities. Results indicate that current research primarily consists of epidemiological and costing/cost-effectiveness/economic studies in India, China, and South Africa, mainly modelling with M72/AS01, BCG revaccination, and hypothetical vaccines. Varying endpoints, vaccine efficacies, and vaccination coverages were used. Globally, new, and repurposed TB vaccines are estimated to save millions of lives. Economically, these vaccines also demonstrate promise with expected cost-effectiveness in most countries. Projected outcomes were dependent on vaccine characteristics, target population, implementation strategy, timing of roll out, TB burden/country context, and vaccination coverage. Potential barriers for vaccine acceptability included TB-related stigma, need for a second dose, and cost, while low pricing, community and civil society engagement and heightened public TB awareness were potential enablers in China, India, and South Africa. Potential implementation strategies considered spanned from mass campaigns to integration within existing vaccine programs and the primary target group studied was the general population, and adults and adolescents. In conclusion, future research must have broader geographical representations to better understand what is needed to inform tailored vaccine programs to accommodate diverse country contexts and population groups to achieve optimal implementation and impact. Furthermore, this review underscores the scarcity of research on acceptability of new and repurposed TB vaccines and their delivery among potential beneficiaries, the most promising implementation strategies, and the health system capabilities necessary for implementation. The absence of this knowledge in these areas emphasizes the crucial need for future research to ensure effective TB vaccine implementation in high burden settings worldwide.
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Affiliation(s)
- Joeri S. Buis
- KNCV Tuberculosis Foundation, The Hague, The Netherlands
| | - Degu Jerene
- KNCV Tuberculosis Foundation, The Hague, The Netherlands
| | - Agnes Gebhard
- KNCV Tuberculosis Foundation, The Hague, The Netherlands
| | - Roel Bakker
- KNCV Tuberculosis Foundation, The Hague, The Netherlands
| | - Arman Majidulla
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Andrew D. Kerkhoff
- Division of HIV, Infectious Diseases and Global Medicine Zuckerberg San Francisco General Hospital and Trauma Center, Center for Tuberculosis, University of California San Francisco, San Francisco, California, United States of America
| | - Rupali J. Limaye
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Puck T. Pelzer
- KNCV Tuberculosis Foundation, The Hague, The Netherlands
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Dale KD, Schwalb A, Coussens AK, Gibney KB, Abboud AJ, Watts K, Denholm JT. Overlooked, dismissed, and downplayed: reversion of Mycobacterium tuberculosis immunoreactivity. Eur Respir Rev 2024; 33:240007. [PMID: 39048129 PMCID: PMC11267292 DOI: 10.1183/16000617.0007-2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 04/16/2024] [Indexed: 07/27/2024] Open
Abstract
Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb). Following infection, immune responses to Mtb antigens can be measured using the tuberculin skin test or an interferon-γ release assay. The gain of Mtb immunoreactivity, a change from a negative to a positive tuberculin skin test or interferon-γ release assay result, is called conversion and has long been used as a measure of Mtb exposure. However, the loss of immunoreactivity (reversion; a positive followed by a negative result) has often been overlooked. Instead, in clinical and epidemiological circles, Mtb immunoreactivity is commonly considered to persist lifelong and confer a lifetime of disease risk. We present a critical review, describing the evidence for reversion from cohort studies, ecological studies and studies of TB progression risk. We outline the inconsistent reasons why reversion has been dismissed from common understanding and present evidence demonstrating that, just as conversion predominantly indicates prior exposure to Mtb antigens, so its opposite, reversion, suggests the reduction or absence of exposure (endogenous or exogenous). Mtb immunoreactivity is dynamic in both individuals and populations and this is why it is useful for stratifying short-term TB progression risk. The neglect of reversion has shaped TB research and policy at all levels, influencing clinical management and skewing Mtb infection risk estimation and transmission modelling, leading to an underestimation of the contribution of re-exposure to the burden of TB, a serious oversight for an infectious disease. More than a century after it was first demonstrated, it is time to incorporate reversion into our understanding of the natural history of TB.
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Affiliation(s)
- Katie D Dale
- Victorian Tuberculosis Program, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Alvaro Schwalb
- TB Modelling Group, TB Centre, London School of Hygiene and Tropical Medicine, London, UK
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Anna K Coussens
- Infectious Diseases and Immune Defence Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, South Africa
| | - Katherine B Gibney
- Victorian Tuberculosis Program, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Infectious Diseases, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Victorian Infectious Disease Service, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Alison J Abboud
- Department of Infectious Diseases, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Krista Watts
- Victorian Tuberculosis Program, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Social Work, School of Health Sciences, University of Melbourne, Melbourne, Australia
| | - Justin T Denholm
- Victorian Tuberculosis Program, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Infectious Diseases, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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Jing S, Xue L, Wang H, Peng Z. Global analysis of an age-structured tuberculosis model with an application to Jiangsu, China. J Math Biol 2024; 88:52. [PMID: 38563991 DOI: 10.1007/s00285-024-02066-z] [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: 09/01/2022] [Revised: 08/31/2023] [Accepted: 02/18/2024] [Indexed: 04/04/2024]
Abstract
Diagnostic delay for TB infected individuals and the lack of TB vaccines for adults are the main challenges to achieve the goals of WHO by 2050. In order to evaluate the impacts of diagnostic delay and vaccination for adults on prevalence of TB, we propose an age-structured model with latent age and infection age, and we incorporate Mycobacterium TB in the environment and vaccination into the model. Diagnostic delay is indicated by the age of infection before receiving treatment. The threshold dynamics are established in terms of the basic reproduction number R 0 . WhenR 0 < 1 , the disease-free equilibrium is globally asymptotically stable, which means that TB epidemic will die out; WhenR 0 = 1 , the disease-free equilibrium is globally attractive; there exists a unique endemic equilibrium and the endemic equilibrium is globally attractive whenR 0 > 1 . We estimate that the basic reproduction numberR 0 = 0.5320 (95% CI (0.3060, 0.7556)) in Jiangsu Province, which means that TB epidemic will die out. However, we find that the annual number of new TB cases by 2050 is 1,151 (95%CI: (138, 8,014)), which means that it is challenging to achieve the goal of WHO by 2050. To this end, we evaluate the possibility of achieving the goals of WHO if we start vaccinating adults and reduce diagnostic delay in 2025. Our results demonstrate that when the diagnostic delay is reduced from longer than four months to four months, or 20% adults are vaccinated, the goal of WHO in 2050 can be achieved, and 73,137 (95%CI: (23,906, 234,086)) and 54,828 (95%CI: (15,811, 206,468)) individuals will be prevented from being infected from 2025 to 2050, respectively. The modeling approaches and simulation results used in this work can help policymakers design control measures to reduce the prevalence of TB.
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Affiliation(s)
- Shuanglin Jing
- College of Mathematical Sciences, Harbin Engineering University, Harbin, 150001, Heilongjiang, China
| | - Ling Xue
- College of Mathematical Sciences, Harbin Engineering University, Harbin, 150001, Heilongjiang, China.
| | - Hao Wang
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada.
| | - Zhihang Peng
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
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Tovar M, Sanz J, Moreno Y. Model-based impact evaluation of new tuberculosis vaccines in aging populations under different modeling scenarios: the case of China. Front Public Health 2024; 12:1302688. [PMID: 38463158 PMCID: PMC10920235 DOI: 10.3389/fpubh.2024.1302688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/05/2024] [Indexed: 03/12/2024] Open
Abstract
Introduction The slow descent in TB burden, the COVID-19 pandemic, along with the rise of multidrug-resistant strains of Mycobacterium tuberculosis, seriously threaten TB control and the goals of the End TB strategy. To fight back, several vaccine candidates are under development, with some of them undergoing the phases 2B and 3 of the development pipeline. The impact of these vaccines on the general population needs to be addressed using disease-transmission models, and, in a country like China, which last year ranked third in number of cases worldwide, and where the population is aging at a fast pace, the impact of TB vaccination campaigns may depend heavily upon the age of targeted populations, the mechanistic descriptions of the TB vaccines and the coupling between TB dynamics and demographic evolution. Methods In this work, we studied the potential impact of a new TB vaccine in China targeting adolescents (15-19 y.o.) or older adults (60-64 y.o.), according to varying vaccine descriptions that represent reasonable mechanisms of action leading to prevention of disease, or prevention of recurrence, each of them targetting specific routes to TB disease. To measure the influence of the description of the coupling between transmission dynamics and aging in TB transmission models, we explored two different approaches to compute the evolution of the contact matrices, which relate to the spreading among different age strata. Results Our findings highlight the dependence of model-based impact estimates on vaccine profiles and the chosen modeling approach for describing the evolution of contact matrices. Our results also show, in line with previous modeling works, that older adult vaccination is a suitable option in China to reduce the incidence of TB as long as the vaccine is able to protect already exposed individuals. Discussion This study underscores the importance of considering vaccine characteristics and demographic dynamics in shaping TB control strategies. In this sense, older adult vaccination emerges as a promising avenue for mitigating TB transmission in China but also remarks the need for tailored intervention strategies aligned with demographic trends.
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Affiliation(s)
- Mario Tovar
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, Spain
| | - Joaquín Sanz
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, Spain
| | - Yamir Moreno
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, Spain
- CENTAI Institute, Turin, Italy
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Bloom BR. A half-century of research on tuberculosis: Successes and challenges. J Exp Med 2023; 220:e20230859. [PMID: 37552470 PMCID: PMC10407785 DOI: 10.1084/jem.20230859] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 08/09/2023] Open
Abstract
Great progress has been made over the past half-century, but TB remains a formidable global health problem, particularly in low- and middle-income countries. Understanding the mechanisms of pathogenesis and necessary and sufficient conditions for protection are critical. The need for inexpensive and sensitive point-of-care diagnostic tests for earlier detection of infection and disease, shorter and less-toxic drug regimens for drug-sensitive and -resistant TB, and a more effective vaccine than BCG is immense. New and better tools, greater support for international research, collaborations, and training will be required to dramatically reduce the burden of this devastating disease which still kills 1.6 million people annually.
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Affiliation(s)
- Barry R. Bloom
- Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Wei X, Fu T, Chen D, Gong W, Zhang S, Long Y, Wu X, Shao Z, Liu K. Spatial-temporal patterns and influencing factors for pulmonary tuberculosis transmission in China: an analysis based on 15 years of surveillance data. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:96647-96659. [PMID: 37580473 DOI: 10.1007/s11356-023-29248-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 08/05/2023] [Indexed: 08/16/2023]
Abstract
Profiting from a series of anti-tuberculosis programs in China, the number of tuberculosis (TB) cases has diminished dramatically in the past decades. However, long-term spatial-temporal variations, regional trends of prevalence, and mechanisms of determinant factors remain unclear. Age-period-cohort analysis and Bayesian space-time hierarchy statistics were conducted to identify high-risk populations and areas in mainland China, and the geographical detector model was used to evaluate the important drivers of the disease. The prevalence of pulmonary TB has declined from 73.3/100,000 in 2004 to 55.45/100,000 in 2018. A bimodal distribution was found in age groups, and the birth cohorts before 1978 had relative higher risk. The high-risk areas were mainly distributed in western China and south-central China, and several provinces in eastern China showed a potential increasing trend, including Beijing, Shanghai, Liaoning, and Guangdong province. The index of night light (Q = 0.46), the population density (Q = 0.41), PM10 (Q = 0.38), urbanization rate (Q = 0.32), and PM 2.5 (Q = 0.31) contributed substantially to the spatial distribution of pulmonary tuberculosis. The identifications of epidemic patterns, high-risk areas and influence factors would help design targeted intervention measures to achieve milestones of the end TB strategy.
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Affiliation(s)
- Xiao Wei
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
- Ministry of Education Key Lab of Hazard Assessment and control in Special Operational Environment, Air Force Medical University, Xi'an, People's Republic of China
| | - Ting Fu
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
- Ministry of Education Key Lab of Hazard Assessment and control in Special Operational Environment, Air Force Medical University, Xi'an, People's Republic of China
| | - Di Chen
- RDFZ Chaoyang Experimental School, Beijing, People's Republic of China
| | - Wenping Gong
- Tuberculosis Prevention and Control Key Laboratory, Senior Department of Tuberculosis, The Eighth Medical Center of PLA General Hospital, Beijing, China
| | - Shuyuan Zhang
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
| | - Yong Long
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
| | - Xubin Wu
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
- Ministry of Education Key Lab of Hazard Assessment and control in Special Operational Environment, Air Force Medical University, Xi'an, People's Republic of China
| | - Zhongjun Shao
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China
- Ministry of Education Key Lab of Hazard Assessment and control in Special Operational Environment, Air Force Medical University, Xi'an, People's Republic of China
| | - Kun Liu
- Department of Epidemiology, School of Public Health, Air Force Medical University, Xi'an, People's Republic of China.
- Ministry of Education Key Lab of Hazard Assessment and control in Special Operational Environment, Air Force Medical University, Xi'an, People's Republic of China.
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Tovar M, Moreno Y, Sanz J. Addressing mechanism bias in model-based impact forecasts of new tuberculosis vaccines. Nat Commun 2023; 14:5312. [PMID: 37658078 PMCID: PMC10474143 DOI: 10.1038/s41467-023-40976-6] [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: 11/04/2022] [Accepted: 08/15/2023] [Indexed: 09/03/2023] Open
Abstract
In tuberculosis (TB) vaccine development, multiple factors hinder the design and interpretation of the clinical trials used to estimate vaccine efficacy. The complex transmission chain of TB includes multiple routes to disease, making it hard to link the vaccine efficacy observed in a trial to specific protective mechanisms. Here, we present a Bayesian framework to evaluate the compatibility of different vaccine descriptions with clinical trial outcomes, unlocking impact forecasting from vaccines whose specific mechanisms of action are unknown. Applying our method to the analysis of the M72/AS01E vaccine trial -conducted on IGRA+ individuals- as a case study, we found that most plausible models for this vaccine needed to include protection against, at least, two over the three possible routes to active TB classically considered in the literature: namely, primary TB, latent TB reactivation and TB upon re-infection. Gathering new data regarding the impact of TB vaccines in various epidemiological settings would be instrumental to improve our model estimates of the underlying mechanisms.
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Affiliation(s)
- M Tovar
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, 50009, Spain
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, 50009, Spain
| | - Y Moreno
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, 50009, Spain
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, 50009, Spain
- Centai Institute S.p.A, 10138, Torino, Italy
| | - J Sanz
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, 50009, Spain.
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, 50009, Spain.
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Scarponi D, Clark RA, Weerasuriya CK, Emery J, Houben RMGJ, White R, McCreesh N. Is neglect of self-clearance biasing TB vaccine impact estimates? BMJ Glob Health 2023; 8:e012799. [PMID: 37558271 PMCID: PMC10414120 DOI: 10.1136/bmjgh-2023-012799] [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: 05/11/2023] [Accepted: 07/13/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Mathematical modelling has been used extensively to estimate the potential impact of new tuberculosis vaccines, with the majority of existing models assuming that individuals with Mycobacterium tuberculosis (Mtb) infection remain at lifelong risk of tuberculosis disease. Recent research provides evidence that self-clearance of Mtb infection may be common, which may affect the potential impact of new vaccines that only take in infected or uninfected individuals. We explored how the inclusion of self-clearance in models of tuberculosis affects the estimates of vaccine impact in China and India. METHODS For both countries, we calibrated a tuberculosis model to a scenario without self-clearance and to various scenarios with self-clearance. To account for the current uncertainty in self-clearance properties, we varied the rate of self-clearance, and the level of protection against reinfection in self-cleared individuals. We introduced potential new vaccines in 2025, exploring vaccines that work in uninfected or infected individuals only, or that are effective regardless of infection status, and modelling scenarios with different levels of vaccine efficacy in self-cleared individuals. We then estimated the relative disease incidence reduction in 2050 for each vaccine compared with the no vaccination scenario. FINDINGS The inclusion of self-clearance increased the estimated relative reductions in incidence in 2050 for vaccines effective only in uninfected individuals, by a maximum of 12% in China and 8% in India. The inclusion of self-clearance increased the estimated impact of vaccines only effective in infected individuals in some scenarios and decreased it in others, by a maximum of 14% in China and 15% in India. As would be expected, the inclusion of self-clearance had minimal impact on estimated reductions in incidence for vaccines that work regardless of infection status. INTERPRETATIONS Our work suggests that the neglect of self-clearance in mathematical models of tuberculosis vaccines does not result in substantially biased estimates of tuberculosis vaccine impact. It may, however, mean that we are slightly underestimating the relative advantages of vaccines that work in uninfected individuals only compared with those that work in infected individuals.
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Affiliation(s)
- Danny Scarponi
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Rebecca A Clark
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Jon Emery
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Rein M G J Houben
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Richard White
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Nicky McCreesh
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Scarponi D, Clark RA, Weerasuriya C, Emery JC, Houben RM, White RG, McCreesh N. Is neglect of self-clearance biassing TB vaccine impact estimates? MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.04.11.23288400. [PMID: 37090535 PMCID: PMC10120796 DOI: 10.1101/2023.04.11.23288400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Background Mathematical modelling has been used extensively to estimate the potential impact of new tuberculosis vaccines, with the majority of existing models assuming that individuals with Mycobacterium tuberculosis (Mtb) infection remain at lifelong risk of tuberculosis disease. Recent research provides evidence that self-clearance of Mtb infection may be common, which may affect the potential impact of new vaccines that only take in infected or uninfected individuals. We explored how the inclusion of self-clearance in models of tuberculosis affects the estimates of vaccine impact in China and India. Methods For both countries, we calibrated a tuberculosis model to a scenario without self-clearance and to various scenarios with self-clearance. To account for the current uncertainty in self-clearance properties, we varied the rate of self-clearance, and the level of protection against reinfection in self-cleared individuals. We introduced potential new vaccines in 2025, exploring vaccines that work in uninfected or infected individuals only, or that are effective regardless of infection status, and modelling scenarios with different levels of vaccine efficacy in self-cleared individuals. We then estimated the relative incidence reduction in 2050 for each vaccine compared to the no vaccination scenario. Findings The inclusion of self-clearance increased the estimated relative reductions in incidence in 2050 for vaccines effective only in uninfected individuals, by a maximum of 12% in China and 8% in India. The inclusion of self-clearance increased the estimated impact of vaccines only effective in infected individuals in some scenarios and decreased it in others, by a maximum of 14% in China and 15% in India. As would be expected, the inclusion of self-clearance had minimal impact on estimated reductions in incidence for vaccines that work regardless of infection status. Interpretations Our work suggests that the neglect of self-clearance in mathematical models of tuberculosis vaccines does not result in substantially biased estimates of tuberculosis vaccine impact. It may, however, mean that we are slightly underestimating the relative advantages of vaccines that work in uninfected individuals only compared to those that work in infected individuals.
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Affiliation(s)
- Danny Scarponi
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Rebecca A Clark
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Chathika Weerasuriya
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Jon C Emery
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Rein Mgj Houben
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Richard G White
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
| | - Nicky McCreesh
- Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine
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Mao JJ, Zang X, Yue WL, Zhai PY, Zhang Q, Li CH, Zhuang X, Liu M, Qin G. Population-level health and economic impacts of introducing Vaccae vaccination in China: a modelling study. BMJ Glob Health 2023; 8:bmjgh-2023-012306. [PMID: 37257938 DOI: 10.1136/bmjgh-2023-012306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/06/2023] [Indexed: 06/02/2023] Open
Abstract
INTRODUCTION Given the ageing epidemic of tuberculosis (TB), China is facing an unprecedented opportunity provided by the first clinically approved next-generation TB vaccine Vaccae, which demonstrated 54.7% efficacy for preventing reactivation from latent infection in a phase III trial. We aim to assess the population-level health and economic impacts of introducing Vaccae vaccination to inform policy-makers. METHODS We evaluated a potential national Vaccae vaccination programme in China initiated in 2024, assuming 20 years of protection, 90% coverage and US$30/dose government contract price. An age-structured compartmental model was adapted to simulate three strategies: (1) no Vaccae; (2) mass vaccination among people aged 15-74 years and (3) targeted vaccination among older adults (60 years). Cost analyses were conducted from the healthcare sector perspective, discounted at 3%. RESULTS Considering postinfection efficacy, targeted vaccination modestly reduced TB burden (~20%), preventing cumulative 8.01 (95% CI 5.82 to 11.8) million TB cases and 0.20 (0.17 to 0.26) million deaths over 2024-2050, at incremental cost-effectiveness ratio of US$4387 (2218 to 10 085) per disability adjusted life year averted. The implementation would require a total budget of US$22.5 (17.6 to 43.4) billion. In contrast, mass vaccination had a larger bigger impact on the TB epidemic, but the overall costs remained high. Although both preinfection and postinfection vaccine efficacy type might have a maximum impact (>40% incidence rate reduction in 2050), it is important that the vaccine price does not exceed US$5/dose. CONCLUSION Vaccae represents a robust and cost-effective choice for TB epidemic control in China. This study may facilitate the practice of evidence-based strategy plans for TB vaccination and reimbursement decision making.
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Affiliation(s)
- Jun-Jie Mao
- Joint Division of Clinical Epidemiology, Affilated Hosptial of Nantong University, School of Public Health of Nantong University, Nantong, Jiangsu, China
| | - Xiao Zang
- Division of Health Policy and Management, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Wan-Lu Yue
- Department of Infectious Diseases, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Pei-Yao Zhai
- Department of Infectious Diseases, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Qiong Zhang
- Research Centre of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Chun-Hu Li
- Joint Division of Clinical Epidemiology, Affilated Hosptial of Nantong University, School of Public Health of Nantong University, Nantong, Jiangsu, China
| | - Xun Zhuang
- Department of Epidemiology and Biostatistics, School of Public Health of Nantong University, Nantong, Jiangsu, China
| | - Min Liu
- Department of Epidemiology and Biostatistics, School of Public Health of Peking University, Beijing, China
| | - Gang Qin
- Joint Division of Clinical Epidemiology, Affilated Hosptial of Nantong University, School of Public Health of Nantong University, Nantong, Jiangsu, China
- National Key Clinical Construction Specialty-Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
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Clark RA, Mukandavire C, Portnoy A, Weerasuriya CK, Deol A, Scarponi D, Iskauskas A, Bakker R, Quaife M, Malhotra S, Gebreselassie N, Zignol M, Hutubessy RCW, Giersing B, Jit M, Harris RC, Menzies NA, White RG. The impact of alternative delivery strategies for novel tuberculosis vaccines in low-income and middle-income countries: a modelling study. Lancet Glob Health 2023; 11:e546-e555. [PMID: 36925175 PMCID: PMC10030455 DOI: 10.1016/s2214-109x(23)00045-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 11/03/2022] [Accepted: 01/13/2023] [Indexed: 03/15/2023]
Abstract
BACKGROUND Tuberculosis is a leading infectious cause of death worldwide. Novel vaccines will be required to reach global targets and reverse setbacks resulting from the COVID-19 pandemic. We estimated the impact of novel tuberculosis vaccines in low-income and middle-income countries (LMICs) in several delivery scenarios. METHODS We calibrated a tuberculosis model to 105 LMICs (accounting for 93% of global incidence). Vaccine scenarios were implemented as the base-case (routine vaccination of those aged 9 years and one-off vaccination for those aged 10 years and older, with country-specific introduction between 2028 and 2047, and 5-year scale-up to target coverage); accelerated scale-up similar to the base-case, but with all countries introducing vaccines in 2025, with instant scale-up; and routine-only (similar to the base-case, but including routine vaccination only). Vaccines were assumed to protect against disease for 10 years, with 50% efficacy. FINDINGS The base-case scenario would prevent 44·0 million (95% uncertainty range 37·2-51·6) tuberculosis cases and 5·0 million (4·6-5·4) tuberculosis deaths before 2050, compared with equivalent estimates of cases and deaths that would be predicted to occur before 2050 with no new vaccine introduction (the baseline scenario). The accelerated scale-up scenario would prevent 65·5 million (55·6-76·0) cases and 7·9 million (7·3-8·5) deaths before 2050, relative to baseline. The routine-only scenario would prevent 8·8 million (95% uncertainty range 7·6-10·1) cases and 1·1 million (0·9-1·2) deaths before 2050, relative to baseline. INTERPRETATION Our results suggest novel tuberculosis vaccines could have substantial impact, which will vary depending on delivery strategy. Including a one-off vaccination campaign will be crucial for rapid impact. Accelerated introduction-at a pace similar to that seen for COVID-19 vaccines-would increase the number of lives saved before 2050 by around 60%. Investment is required to support vaccine development, manufacturing, prompt introduction, and scale-up. FUNDING WHO (2020/985800-0). TRANSLATIONS For the French, Spanish, Italian and Dutch translations of the abstract see Supplementary Materials section.
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Affiliation(s)
- Rebecca A Clark
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Vaccine Centre, London School of Hygiene & Tropical Medicine, London, UK.
| | - Christinah Mukandavire
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Allison Portnoy
- Center for Health Decision Science, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Chathika K Weerasuriya
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Arminder Deol
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Danny Scarponi
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Andrew Iskauskas
- Department of Mathematical Sciences, Durham University, Durham, UK
| | - Roel Bakker
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; KNCV Tuberculosis Foundation, The Hague, Netherlands
| | - Matthew Quaife
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | | | | | - Matteo Zignol
- Global TB Programme, World Health Organization, Geneva, Switzerland
| | - Raymond C W Hutubessy
- Department of Immunization, Vaccines, and Biologicals, World Health Organization, Geneva, Switzerland
| | - Birgitte Giersing
- The Initiative for Vaccine Research, World Health Organization, Geneva, Switzerland
| | - Mark Jit
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Rebecca C Harris
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Global Medical Evidence Generation for Influenza Vaccines, Sanofi Pasteur, Singapore
| | - Nicolas A Menzies
- Center for Health Decision Science, Harvard TH Chan School of Public Health, Boston, MA, USA; Department of Global Health and Population, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Richard G White
- TB Modelling Group and TB Centre, London School of Hygiene & Tropical Medicine, London, UK; Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Jayawardana S, Weerasuriya CK, Pelzer PT, Seeley J, Harris RC, Tameris M, Tait D, White RG, Asaria M. Feasibility of novel adult tuberculosis vaccination in South Africa: a cost-effectiveness and budget impact analysis. NPJ Vaccines 2022; 7:138. [PMID: 36344523 PMCID: PMC9640704 DOI: 10.1038/s41541-022-00554-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
Early trials of novel vaccines against tuberculosis (TB) in adults have suggested substantial protection against TB. However, little is known about the feasibility and affordability of rolling out such vaccines in practice. We conducted expert interviews to identify plausible vaccination implementation strategies for the novel M72/AS01E vaccine candidate. The strategies were defined in terms of target population, coverage, vaccination schedule and delivery mode. We modelled these strategies to estimate long-term resource requirements and health benefits arising from vaccination over 2025-2050. We presented these to experts who excluded strategies that were deemed infeasible, and estimated cost-effectiveness and budget impact for each remaining strategy. The four strategies modelled combined target populations: either everyone aged 18-50, or all adults living with HIV, with delivery strategies: either a mass campaign followed by routine vaccination of 18-year olds, or two mass campaigns 10 years apart. Delivering two mass campaigns to all 18-50-year olds was found to be the most cost-effective strategy conferring the greatest net health benefit of 1.2 million DALYs averted having a probability of being cost-effective of 65-70%. This strategy required 38 million vaccine courses to be delivered at a cost of USD 507 million, reducing TB-related costs by USD 184 million while increasing ART costs by USD 79 million. A suitably designed adult TB vaccination programme built around novel TB vaccines is likely to be cost-effective and affordable given the resource and budget constraints in South Africa.
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Affiliation(s)
- Sahan Jayawardana
- Department of Health Policy, London School of Economics (LSE), London, UK.
| | - Chathika K Weerasuriya
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Puck T Pelzer
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
- KNCV Tuberculosis foundation, Hague, Netherlands
| | - Janet Seeley
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Rebecca C Harris
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
- Sanofi Pasteur, Singapore, Singapore
| | - Michele Tameris
- South African Tuberculosis Vaccine Initiative (SATVI), Department of Pathology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town (UCT), Cape Town, South Africa
| | - Dereck Tait
- Independent consultant, Cape Town, South Africa
| | - Richard G White
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Miqdad Asaria
- Department of Health Policy, London School of Economics (LSE), London, UK
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Age-period-cohort analysis of pulmonary tuberculosis reported incidence, China, 2006-2020. Infect Dis Poverty 2022; 11:85. [PMID: 35902982 PMCID: PMC9331155 DOI: 10.1186/s40249-022-01009-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/13/2022] [Indexed: 11/22/2022] Open
Abstract
Background Tuberculosis (TB) poses a severe public health challenge in China and worldwide. This study evaluated the effects of age, period, and birth cohort on reported incidence trends of TB based on population and refined the characteristics of high-risk groups. Methods Aggregate data that reported pulmonary tuberculosis (PTB) cases from China Tuberculosis Management Information System (TBIMS) from 2006 to 2020 were used to analyze effect coefficients through the age–period–cohort (APC) model based on intrinsic estimator (IE) method, and converted them into relative risk (RR) to estimate trends. Results A total of 14.82 million cases of PTB were reported in China from 2006 to 2020, showing a continuous downward trend. The reporting rate increased with age by age group, with 70–74 years old being 2–3 times higher than that in 20–24 years old. APC analysis model showed that age effects were bimodal in 20–24 years old [RR = 2.29, 95% confidence interval (CI): 1.73–3.03] and 70–74 years old (RR = 1.95, 95% CI: 1.67–2.27), and lower than the overall average in the groups under 15 years old. Stratified results showed that the risk was higher for women under age 40 than men and higher for men over 40. The risk was higher in urban than in rural areas under 30 years old and slightly higher in rural than in urban between 30 and 64 years old. The risk for 15–34 years old was significantly higher in the east than in other regions. The period effects showed a decreasing trend, and the risk was higher in rural in recent years. Except for cohorts born in 1961–1965 and 2001–2005, where the RR increased, the later the cohort was born, the lower the risk. The cohort 1926–1930 in eastern had the highest risk (RR = 3.49, 95% CI: 2.44–4.98). Conclusions The reported incidence of PTB continued to decline in China from 2006 to 2020. The young (20–24 years old) and the elderly (70–74 years old) were equally at high risk. There were differences in the age, period and cohort effects on PTB incidence among gender, urban–rural and regions. Our findings better reflected the characteristics of high-risk populations, thus contributing to the development of timely and effective intervention strategies, and providing clues for etiological research. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-01009-4.
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Horton KC, White RG, Hoa NB, Nguyen HV, Bakker R, Sumner T, Corbett EL, Houben RMGJ. Population benefits of addressing programmatic and social determinants of gender disparities in tuberculosis in Viet Nam: A modelling study. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000784. [PMID: 36962475 PMCID: PMC10021793 DOI: 10.1371/journal.pgph.0000784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/23/2022] [Indexed: 11/18/2022]
Abstract
High prevalence of infectious tuberculosis among men suggests potential population-wide benefits from addressing programmatic and social determinants of gender disparities. Utilising a sex-stratified compartmental transmission model calibrated to tuberculosis burden estimates for Viet Nam, we modelled interventions to increase active case finding, to reduce tobacco smoking, and to reduce alcohol consumption by 2025 in line with national and global targets. For each intervention, we examined scenarios differentially targeting men and women and evaluated impact on tuberculosis morbidity and mortality in men, women, and children in 2035. Active case finding interventions targeting men projected greater reductions in tuberculosis incidence in men, women, and children (16.2%, uncertainty interval, UI, 11.4-23.0%, 11.8%, UI 8.0-18.6%, and 21.5%, UI 16.9-28.5%, respectively) than those targeting women (5.2%, UI 3.8-7.1%, 5.4%, UI 3.9-7.3%, and 8.6%, UI 6.9-10.7%, respectively). Projected reductions in tuberculosis incidence for interventions to reduce male tobacco smoking and alcohol consumption were greatest for men (17.4%, UI 11.8-24.7%, and 11.0%, UI 5.4-19.4%, respectively), but still substantial for women (6.9%, UI 3.8-12.5%, and 4.4%, UI 1.9-10.6%, respectively) and children (12.7%, UI 8.4-19.0%, and 8.0%, UI 3.9-15.0%, respectively). Comparable interventions targeting women projected limited impact, with declines of 0.3% (UI 0.2%-0.3%) and 0.1% (UI 0.0%-0.1%), respectively. Addressing programmatic and social determinants of men's tuberculosis burden has population-wide benefits. Future interventions to increase active case finding, to reduce tobacco smoking, and to reduce harmful alcohol consumption, whilst not ignoring women, should focus on men to most effectively reduce tuberculosis morbidity and mortality in men, women, and children.
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Affiliation(s)
- Katherine C. Horton
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- TB Modelling Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Richard G. White
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- TB Modelling Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Hai Viet Nguyen
- National Tuberculosis Control Programme, Hanoi, Viet Nam
- Department of Global Health and Amsterdam Institute of Global Health and Development, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Roel Bakker
- Skardahl IT Solutions, Delft, The Netherlands
| | - Tom Sumner
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- TB Modelling Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Elizabeth L. Corbett
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Rein M. G. J. Houben
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- TB Modelling Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
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15
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Wen Z, Li T, Zhu W, Chen W, Zhang H, Wang W. Effect of different interventions for latent tuberculosis infections in China: a model-based study. BMC Infect Dis 2022; 22:488. [PMID: 35606696 PMCID: PMC9125978 DOI: 10.1186/s12879-022-07465-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 05/13/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Tuberculosis (TB) has a serious impact on people's health. China is one of 30 countries that has a high TB burden. As the currently decreasing speed of the incidence of TB, the WHO's goal of "End TB Strategy" is hard to achieve by 2035. As a result, a SEIR model that determines the impact of different tuberculosis preventive treatments (TPTs) in different age groups, and the effect of different interventions on latent TB infections (LTBIs) in China is developed. METHODS A Susceptible-Exposed-Infectious-Recovered (SEIR) model was established. Goodness-of-fit tests were used to assess model performance. Predictive analysis was used to assess the effect of different interventions on LTBIs and achieving the goals of the "End TB Strategy". RESULTS The Chi-square test indicated the model provided a good statistical fit to previous data on the incidence of TB (χ2 = 0.3085, p > 0.999). The 1HP treatment regimen (daily rifapentine + isoniazid for 4 weeks) was most effective in reducing the number of TB cases by 2035. The model indicated that several strategies could achieve the 2035 target of the "End TB Strategy": completion of active case finding (ACF) for LTBI and TPT nation-wide within 5 years; completion of ACF for LTBIs and TPT within 2 years in high-incidence areas; completion of TPT in the elderly within 2 years; or introduction of a new vaccine in which the product of annual doses and vaccine efficiency in the three age groups above 14 years old reached 10.5 million. CONCLUSION The incidence of TB in China declined gradually from 2005 to 2019. Implementation of ACF for LTBIs and TPT nation-wide or in areas with high incidence, in the elderly, or administration of a new and effective vaccine could greatly reduce the number of TB cases and achieve the 2035 target of the "End TB Strategy" in China.
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Affiliation(s)
- Zexuan Wen
- Department of Epidemiology, School of Public Health, Fudan University, Shanghai, 200032, China
| | - Tao Li
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 100050, China
| | - Wenlong Zhu
- Department of Epidemiology, School of Public Health, Fudan University, Shanghai, 200032, China.,Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China
| | - Wei Chen
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 100050, China
| | - Hui Zhang
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 100050, China.
| | - Weibing Wang
- Department of Epidemiology, School of Public Health, Fudan University, Shanghai, 200032, China. .,Key Laboratory of Public Health Safety of Ministry of Education, Fudan University, Shanghai, 200032, China. .,Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China.
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16
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Pelzer PT, Seeley J, Sun FY, Tameris M, Tao L, Yanlin Z, Moosan H, Weerasuriya C, Asaria M, Jayawardana S, White RG, Harris RC. Potential implementation strategies, acceptability, and feasibility of new and repurposed TB vaccines. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000076. [PMID: 36962104 PMCID: PMC10021736 DOI: 10.1371/journal.pgph.0000076] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/15/2021] [Indexed: 12/27/2022]
Abstract
Recently, two Phase 2B tuberculosis vaccine trials reported positive efficacy results in adolescents and adults. However, experience in vaccinating these age groups is limited. We identified potential implementation strategies for the M72/AS01E vaccination and BCG-revaccination-like candidates and explored their acceptability and feasibility. We conducted in-depth semi-structured interviews among key decision makers to identify implementation strategies and target groups in South Africa, India, and China. Thematic and deductive analysis using a coding framework were used to identify themes across and within settings. In all three countries there was interest in novel TB vaccines, with school-attending adolescents named as a likely target group. In China and India, older people were also identified as a target group. Routine vaccination was preferred in all countries due to stigma and logistical issues with targeted mass campaigns. Perceived benefits for implementation of M72/AS01E were the likely efficacy in individuals with Mycobacterium tuberculosis (Mtb) infection and efficacy for people living with HIV. Perceived challenges for M72/AS01E included the infrastructure and the two-dose regimen required. Stakeholders valued the familiarity of BCG but were concerned about the adverse effects in people living with HIV, a particular concern in South Africa. Implementation challenges and opportunities were identified in all three countries. Our study provides crucial information for implementing novel TB vaccines in specific target groups and on country specific acceptability and feasibility. Key groups for vaccine implementation in these settings were identified, and should be included in clinical trials and implementation planning.
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Affiliation(s)
- Puck T. Pelzer
- KNCV Tuberculosis Foundation, Amsterdam, Netherlands
- London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom
| | - Janet Seeley
- London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom
| | - Fiona Yueqian Sun
- London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom
| | - Michele Tameris
- South African Tuberculosis Vaccine Initiative (SATVI), Department of Pathology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town (UCT), Cape Town, South Africa
| | - Li Tao
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | - Zhao Yanlin
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | - Hisham Moosan
- Health Action by People, Thriuvananthapuram, Kerala, India
| | | | - Miqdad Asaria
- London School of Economics (LSE), London, United Kingdom
| | | | - Richard G. White
- London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom
| | - Rebecca C. Harris
- London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom
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Evaluating Strategies For Tuberculosis to Achieve the Goals of WHO in China: A Seasonal Age-Structured Model Study. Bull Math Biol 2022; 84:61. [PMID: 35486232 DOI: 10.1007/s11538-022-01019-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 03/28/2022] [Indexed: 11/02/2022]
Abstract
Although great progress has been made in the prevention and mitigation of TB in the past 20 years, China is still the third largest contributor to the global burden of new TB cases, accounting for 833,000 new cases in 2019. Improved mitigation strategies, such as vaccines, diagnostics, and treatment, are needed to meet goals of WHO. Given the huge variability in the prevalence of TB across age-groups in China, the vaccination, diagnostic techniques, and treatment for different age-groups may have different effects. Moreover, the statistics data of TB cases show significant seasonal fluctuations in China. In view of the above facts, we propose a non-autonomous differential equation model with age structure and seasonal transmission rate. We derive the basic reproduction number, [Formula: see text], and prove that the unique disease-free periodic solution, [Formula: see text] is globally asymptotically stable when [Formula: see text], while the disease is uniformly persistent and at least one positive periodic solution exists when [Formula: see text]. We estimate that the basic reproduction number [Formula: see text] ([Formula: see text]), which means that TB is uniformly persistent. Our results demonstrate that vaccinating susceptible individuals whose ages are over 65 and between 20 and 24 is much more effective in reducing the prevalence of TB, and each of the improved vaccination strategy, diagnostic strategy, and treatment strategy leads to substantial reductions in the prevalence of TB per 100,000 individuals compared with current approaches, and the combination of the three strategies is more effective. Scenario A (i.e., coverage rate [Formula: see text], diagnosis rate [Formula: see text], relapse rate [Formula: see text]) is the best and can reduce the prevalence of TB per 100,000 individuals by [Formula: see text] and [Formula: see text] in 2035 and 2050, respectively. Although the improved strategies will significantly reduce the incidence rate of TB, it is challenging to achieve the goal of WHO in 2050. Our findings can provide guidance for public health authorities in projecting effective mitigation strategies of TB.
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Weerasuriya CK, Harris RC, McQuaid CF, Gomez GB, White RG. Updating age-specific contact structures to match evolving demography in a dynamic mathematical model of tuberculosis vaccination. PLoS Comput Biol 2022; 18:e1010002. [PMID: 35452459 PMCID: PMC9067655 DOI: 10.1371/journal.pcbi.1010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 05/04/2022] [Accepted: 03/08/2022] [Indexed: 11/18/2022] Open
Abstract
We investigated the effects of updating age-specific social contact matrices to match evolving demography on vaccine impact estimates. We used a dynamic transmission model of tuberculosis in India as a case study. We modelled four incremental methods to update contact matrices over time, where each method incorporated its predecessor: fixed contact matrix (M0), preserved contact reciprocity (M1), preserved contact assortativity (M2), and preserved average contacts per individual (M3). We updated the contact matrices of a deterministic compartmental model of tuberculosis transmission, calibrated to epidemiologic data between 2000 and 2019 derived from India. We additionally calibrated the M0, M2, and M3 models to the 2050 TB incidence rate projected by the calibrated M1 model. We stratified age into three groups, children (<15y), adults (≥15y, <65y), and the elderly (≥65y), using World Population Prospects demographic data, between which we applied POLYMOD-derived social contact matrices. We simulated an M72-AS01E-like tuberculosis vaccine delivered from 2027 and estimated the per cent TB incidence rate reduction (IRR) in 2050 under each update method. We found that vaccine impact estimates in all age groups remained relatively stable between the M0–M3 models, irrespective of vaccine-targeting by age group. The maximum difference in impact, observed following adult-targeted vaccination, was 7% in the elderly, in whom we observed IRRs of 19% (uncertainty range 13–32), 20% (UR 13–31), 22% (UR 14–37), and 26% (UR 18–38) following M0, M1, M2 and M3 updates, respectively. We found that model-based TB vaccine impact estimates were relatively insensitive to demography-matched contact matrix updates in an India-like demographic and epidemiologic scenario. Current model-based TB vaccine impact estimates may be reasonably robust to the lack of contact matrix updates, but further research is needed to confirm and generalise this finding. Mathematical models are increasingly used to predict the impact of new and existing tools, e.g., vaccines, that aim to control the transmission of infectious diseases. Within these models, investigators often assume that individuals contact each other according to specific patterns, particularly between and within different age groups. These patterns are typically derived from surveys of social contact or other models and reflect the particular age composition of their source population. However, when models are set over long time scales, e.g., decades, population age composition is likely to change. Despite this reality, few models update their contact patterns to match changing age composition. Furthermore, none have assessed whether their final estimates of disease-control intervention impact are affected by updating contact patterns. We measured whether different techniques to update social contact patterns to match evolving demography produce different vaccine impact estimates, using a mathematical model of tuberculosis set in an India-like scenario between 2025–2050. We found that vaccine impact was stable across a range of different update methods. Thus, existing model-based vaccine impact estimates may be stable to a lack of these updates, but further work is required to confirm these findings.
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Affiliation(s)
- Chathika Krishan Weerasuriya
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Rebecca Claire Harris
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher Finn McQuaid
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gabriela B. Gomez
- Department of Global Health & Development, Faculty of Public Health & Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Richard G. White
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Lin Q, Shrestha S, Zhao S, Chiu APY, Liu Y, Yu C, Tao N, Li Y, Shao Y, He D, Li H. Changing Epidemiology of TB in Shandong, China Driven by Demographic Changes. Front Med (Lausanne) 2022; 9:810382. [PMID: 35355613 PMCID: PMC8959836 DOI: 10.3389/fmed.2022.810382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 01/31/2022] [Indexed: 11/24/2022] Open
Abstract
Tuberculosis (TB) incidence has been in steady decline in China over the last few decades. However, ongoing demographic transition, fueled by aging, and massive internal migration could have important implications for TB control in the future. We collated data on TB notification, demography, and drug resistance between 2004 and 2017 across seven cities in Shandong, the second most populous province in China. Using these data, and age-period-cohort models, we (i) quantified heterogeneities in TB incidence across cities, by age, sex, resident status, and occupation and (ii) projected future trends in TB incidence, including drug-resistant TB (DR-TB). Between 2006 and 2017, we observed (i) substantial variability in the rates of annual change in TB incidence across cities, from -4.84 to 1.52%; (ii) heterogeneities in the increments in the proportion of patients over 60 among reported TB cases differs from 2 to 13%, and from 0 to 17% for women; (iii) huge differences across cities in the annual growths in TB notification rates among migrant population between 2007 and 2017, from 2.81 cases per 100K migrants per year in Jinan to 22.11 cases per 100K migrants per year in Liaocheng, with drastically increasing burden of TB cases from farmers; and (iv) moderate and stable increase in the notification rates of DR-TB in the province. All of these trends were projected to continue over the next decade, increasing heterogeneities in TB incidence across cities and between populations. To sustain declines in TB incidence and to prevent an increase in Multiple DR-TB (MDR-TB) in the future in China, future TB control strategies may (i) need to be tailored to local demography, (ii) prioritize key populations, such as elderly and internal migrants, and (iii) enhance DR-TB surveillance.
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Affiliation(s)
- Qianying Lin
- Department of Applied Mathematics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.,Michigan Institute for Data Science, University of Michigan, Ann Arbor, MI, United States
| | - Sourya Shrestha
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Shi Zhao
- Department of Applied Mathematics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.,JC School of Public Health and Primary Care, Chinese University of Hong Kong, Johns Hopkins University, Shatin, Hong Kong SAR, China
| | - Alice P Y Chiu
- Department of Applied Mathematics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Yao Liu
- Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | | | - Ningning Tao
- Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yifan Li
- Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yang Shao
- Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Huaichen Li
- Department of Respiratory and Critical Care Medicine, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
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20
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Cobelens F, Suri RK, Helinski M, Makanga M, Weinberg AL, Schaffmeister B, Deege F, Hatherill M. Accelerating research and development of new vaccines against tuberculosis: a global roadmap. THE LANCET. INFECTIOUS DISEASES 2022; 22:e108-e120. [PMID: 35240041 PMCID: PMC8884775 DOI: 10.1016/s1473-3099(21)00810-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 12/03/2022]
Abstract
To eliminate tuberculosis globally, a new, effective, and affordable vaccine is urgently needed, particularly for use in adults and adolescents in low-income and middle-income countries. We have created a roadmap that lists the actions needed to accelerate tuberculosis vaccine research and development using a participatory process. The vaccine pipeline needs more diverse immunological approaches, antigens, and platforms. Clinical development can be accelerated by validated preclinical models, agreed laboratory correlates of protection, efficient trial designs, and validated endpoints. Determining the public health impact of new tuberculosis vaccines requires understanding of a country's demand for a new tuberculosis vaccine, how to integrate vaccine implementation with ongoing tuberculosis prevention efforts, cost, and national and global demand to stimulate vaccine production. Investments in tuberculosis vaccine research and development need to be increased, with more diversity of funding sources and coordination between these funders. Open science is important to enhance the efficiency of tuberculosis vaccine research and development including early and freely available publication of study findings and effective mechanisms for sharing datasets and specimens. There is a need for increased engagement of industry vaccine developers, for increased political commitment for new tuberculosis vaccines, and to address stigma and vaccine hesitancy. The unprecedented speed by which COVID-19 vaccines have been developed and introduced provides important insight for tuberculosis vaccine research and development.
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Affiliation(s)
- Frank Cobelens
- Department of Global Health and Amsterdam Institute for Global Health and Development, Amsterdam University Medical Centers, Amsterdam, Netherlands.
| | - Rajinder Kumar Suri
- Department of Governance and Strategy, Developing Countries Vaccine Manufacturers' Network International, Nyon, Switzerland
| | - Michelle Helinski
- European & Developing Countries Clinical Trials Partnership, The Hague, Netherlands
| | - Michael Makanga
- European & Developing Countries Clinical Trials Partnership, The Hague, Netherlands
| | - Ana Lúcia Weinberg
- European & Developing Countries Clinical Trials Partnership, The Hague, Netherlands
| | | | | | - Mark Hatherill
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
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21
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Kochhar S, Barreira D, Beattie P, Cavaleri M, Cravioto A, Frick MW, Ginsberg AM, Hudson I, Kaslow DC, Kurtz S, Lienhardt C, Madhi SA, Morgan C, Momeni Y, Patel D, Rees H, Rogalski-Salter T, Schmidt A, Semete-Makokotlela B, Voss G, White RG, Zignol M, Giersing B. Building the concept for WHO Evidence Considerations for Vaccine Policy (ECVP): Tuberculosis vaccines intended for adults and adolescents as a test case. Vaccine 2022; 40:1681-1690. [PMID: 35164990 PMCID: PMC8914344 DOI: 10.1016/j.vaccine.2021.10.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 12/17/2022]
Abstract
Currently, no formal mechanisms or systematic approaches exist to inform developers of new vaccines of the evidence anticipated to facilitate global policy recommendations, before a vaccine candidate approaches regulatory approval at the end of pre-licensure efficacy studies. Consequently, significant delays may result in vaccine introduction and uptake, while post-licensure data are generated to support a definitive policy decision. To address the uncertainties of the evidence-to-recommendation data needs and to mitigate the risk of delays between vaccine recommendation and use, WHO is evaluating the need for and value of a new strategic alignment tool: Evidence Considerations for Vaccine Policy (ECVP). EVCPs aim to fill a critical current gap by providing early (pre-phase 3 study design) information on the anticipated clinical trial and observational data or evidence that could support WHO and/or policy decision making for new vaccines in priority disease areas. The intent of ECVPs is to inform vaccine developers, funders, and other key stakeholders, facilitating stakeholder alignment in their strategic planning for late stage vaccine development. While ECVPs are envisaged as a tool to support dialogue on evidence needs between regulators and policy makers at the national, regional and global level, development of an ECVP will not preclude or supersede the independent WHO's Strategic Advisory Group of Experts on Immunization (SAGE) evidence to recommendation (EtR) process that is required for all vaccines seeking WHO policy recommendation. Tuberculosis (TB) vaccine candidates intended for use in the adolescent and adult target populations comprise a portfolio of priority vaccines in late-stage clinical development. As such, TB vaccines intended for use in this target population provide a 'test case' to further develop the ECVP concept, and develop the first WHO ECVP considerations guidance.
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Affiliation(s)
- Sonali Kochhar
- Global Healthcare Consulting, New Delhi, India; Department of Global Health, University of Washington, Seattle, WA, USA.
| | | | - Pauline Beattie
- European & Developing Countries Clinical Trials Partnership (EDCTP), The Hague, the Netherlands
| | - Marco Cavaleri
- European Medicines Agency (EMA), Amsterdam, the Netherlands
| | - Alejandro Cravioto
- Faculty of Medicine of the National Autonomous University of Mexico, Mexico
| | | | | | - Ian Hudson
- Bill & Melinda Gates Foundation, London, UK
| | | | | | - Christian Lienhardt
- Unité Mixte Internationale TransVIHMI (Université de Montpellier, UMI 233 IRD, U1175 INSERM), Institut de Recherche pour le Développement (IRD), Montpellier, France; Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Shabir A Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Christopher Morgan
- Jhpiego, Baltimore, USA; School of Population and Global Health, University of Melbourne, Victoria, Australia; Burnet Institute, Melbourne, Australia
| | | | | | - Helen Rees
- Wits Reproductive Health and HIV Institute, University of Witwatersrand, Johannesburg, South Africa
| | | | - Alexander Schmidt
- Bill & Melinda Gates Medical Research Institute, Cambridge, MA, United States
| | | | - Gerald Voss
- TuBerculosis Vaccine Initiative (TBVI), Lelystad, the Netherlands
| | - Richard G White
- TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, UK
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22
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Harris RC, Quaife M, Weerasuriya C, Gomez GB, Sumner T, Bozzani F, White RG. Cost-effectiveness of routine adolescent vaccination with an M72/AS01 E-like tuberculosis vaccine in South Africa and India. Nat Commun 2022; 13:602. [PMID: 35105879 PMCID: PMC8807591 DOI: 10.1038/s41467-022-28234-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 01/07/2022] [Indexed: 12/26/2022] Open
Abstract
The M72/AS01E tuberculosis vaccine showed 50% (95%CI: 2-74%) efficacy in a phase 2B trial in preventing active pulmonary tuberculosis disease, but potential cost-effectiveness of adolescent immunisation is unknown. We estimated the impact and cost-effectiveness of six scenarios of routine adolescent M72/AS01E-like vaccination in South Africa and India. All scenarios suggested an M72/AS01E-like vaccine would be highly (94-100%) cost-effective in South Africa compared to a cost-effectiveness threshold of $2480/disability-adjusted life-year (DALY) averted. For India, a prevention of disease vaccine, effective irrespective of recipient's M. tuberculosis infection status at time of administration, was also highly likely (92-100%) cost-effective at a threshold of $264/DALY averted; however, a prevention of disease vaccine, effective only if the recipient was already infected, had 0-6% probability of cost-effectiveness. In both settings, vaccinating 50% of 18 year-olds was similarly cost-effective to vaccinating 80% of 15 year-olds, and more cost-effective than vaccinating 80% of 10 year-olds. Vaccine trials should include adolescents to ensure vaccines can be delivered to this efficient-to-target population.
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Affiliation(s)
- Rebecca C Harris
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK. .,Sanofi Pasteur, Singapore, Singapore.
| | - Matthew Quaife
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Chathika Weerasuriya
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Gabriela B Gomez
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK.,Sanofi Pasteur, Lyon, France
| | - Tom Sumner
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Fiammetta Bozzani
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Richard G White
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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23
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Renardy M, Kirschner D, Eisenberg M. Structural identifiability analysis of age-structured PDE epidemic models. J Math Biol 2022; 84:9. [PMID: 34982260 PMCID: PMC8724244 DOI: 10.1007/s00285-021-01711-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 10/21/2021] [Accepted: 12/22/2021] [Indexed: 11/24/2022]
Abstract
Computational and mathematical models rely heavily on estimated parameter values for model development. Identifiability analysis determines how well the parameters of a model can be estimated from experimental data. Identifiability analysis is crucial for interpreting and determining confidence in model parameter values and to provide biologically relevant predictions. Structural identifiability analysis, in which one assumes data to be noiseless and arbitrarily fine-grained, has been extensively studied in the context of ordinary differential equation (ODE) models, but has not yet been widely explored for age-structured partial differential equation (PDE) models. These models present additional difficulties due to increased number of variables and partial derivatives as well as the presence of boundary conditions. In this work, we establish a pipeline for structural identifiability analysis of age-structured PDE models using a differential algebra framework and derive identifiability results for specific age-structured models. We use epidemic models to demonstrate this framework because of their wide-spread use in many different diseases and for the corresponding parallel work previously done for ODEs. In our application of the identifiability analysis pipeline, we focus on a Susceptible-Exposed-Infected model for which we compare identifiability results for a PDE and corresponding ODE system and explore effects of age-dependent parameters on identifiability. We also show how practical identifiability analysis can be applied in this example.
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Affiliation(s)
- Marissa Renardy
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, USA
| | - Denise Kirschner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, USA
| | - Marisa Eisenberg
- Department of Epidemiology, University of Michigan, Ann Arbor, USA
- Department of Mathematics, University of Michigan, Ann Arbor, USA
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24
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After 100 Years of BCG Immunization against Tuberculosis, What Is New and Still Outstanding for This Vaccine? Vaccines (Basel) 2021; 10:vaccines10010057. [PMID: 35062718 PMCID: PMC8778337 DOI: 10.3390/vaccines10010057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/17/2021] [Accepted: 12/29/2021] [Indexed: 12/14/2022] Open
Abstract
In 2021, most of the world was reasonably still concerned about the COVID-19 pandemic, how cases were up and down in different countries, how the vaccination campaigns were ongoing, and most people were familiar with the speed with which vaccines against SARS-Co-V2 were developed, analyzed, and started to be applied in an attempt to curb the pandemic. Because of this, it may have somehow passed relatively inadvertently for people outside of the field that the vaccine used to control tuberculosis (TB), Mycobacterium bovis Bacille Calmette-Guérin (BCG), was first applied to humans a century ago. Over these years, BCG has been the vaccine applied to most human beings in the world, despite its known lack of efficacy to fully prevent respiratory TB. Several strategies have been employed in the last 20 years to produce a novel vaccine that would replace, or boost, immunity and protection elicited by BCG. In this work, to avoid potential redundancies with recently published reviews, I only aim to present my current thoughts about some of the latest findings and outstanding questions that I consider worth investigating to help develop a replacement or modified BCG in order to successfully fight TB, based on BCG itself.
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25
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Olbrich L, Stockdale L, Basu Roy R, Song R, Cicin-Sain L, Whittaker E, Prendergast AJ, Fletcher H, Seddon JA. Understanding the interaction between cytomegalovirus and tuberculosis in children: The way forward. PLoS Pathog 2021; 17:e1010061. [PMID: 34882748 PMCID: PMC8659711 DOI: 10.1371/journal.ppat.1010061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Over 1 million children develop tuberculosis (TB) each year, with a quarter dying. Multiple factors impact the risk of a child being exposed to Mycobacterium tuberculosis (Mtb), the risk of progressing to TB disease, and the risk of dying. However, an emerging body of evidence suggests that coinfection with cytomegalovirus (CMV), a ubiquitous herpes virus, impacts the host response to Mtb, potentially influencing the probability of disease progression, type of TB disease, performance of TB diagnostics, and disease outcome. It is also likely that infection with Mtb impacts CMV pathogenesis. Our current understanding of the burden of these 2 diseases in children, their immunological interactions, and the clinical consequence of coinfection is incomplete. It is also unclear how potential interventions might affect disease progression and outcome for TB or CMV. This article reviews the epidemiological, clinical, and immunological literature on CMV and TB in children and explores how the 2 pathogens interact, while also considering the impact of HIV on this relationship. It outlines areas of research uncertainty and makes practical suggestions as to potential studies that might address these gaps. Current research is hampered by inconsistent definitions, study designs, and laboratory practices, and more consistency and collaboration between researchers would lead to greater clarity. The ambitious targets outlined in the World Health Organization End TB Strategy will only be met through a better understanding of all aspects of child TB, including the substantial impact of coinfections.
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Affiliation(s)
- Laura Olbrich
- Division of Infectious Diseases and Tropical Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
- German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
| | - Lisa Stockdale
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, The Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Robindra Basu Roy
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rinn Song
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Luka Cicin-Sain
- Helmholtz Centre for Infection Research, Braunschweig, Germany
- German Centre for Infection Research (DZIF), Partner site Hannover-Braunschweig, Braunschweig, Germany
| | - Elizabeth Whittaker
- Department of Infectious Diseases, Imperial College London, London, United Kingdom
- Department of Paediatric Infectious Diseases, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Andrew J. Prendergast
- Blizard Institute, Queen Mary University of London, London, United Kingdom
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
| | - Helen Fletcher
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - James A. Seddon
- Department of Infectious Diseases, Imperial College London, London, United Kingdom
- Department of Paediatric Infectious Diseases, Imperial College Healthcare NHS Trust, London, United Kingdom
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Stellenbosch University, Cape Town, South Africa
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26
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Affordability of Adult Tuberculosis Vaccination in India and China: A Dynamic Transmission Model-Based Analysis. Vaccines (Basel) 2021; 9:vaccines9030245. [PMID: 33799544 PMCID: PMC7998179 DOI: 10.3390/vaccines9030245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/25/2021] [Accepted: 03/06/2021] [Indexed: 11/30/2022] Open
Abstract
New tuberculosis vaccines have made substantial progress in the development pipeline. Previous modelling suggests that adolescent/adult mass vaccination may cost-effectively contribute towards achieving global tuberculosis control goals. These analyses have not considered the budgetary feasibility of vaccine programmes. We estimate the maximum total cost that the public health sectors in India and China should expect to pay to introduce a M72/AS01E-like vaccine deemed cost-effective at country-specific willingness to pay thresholds for cost-effectiveness. To estimate the total disability adjusted life years (DALYs) averted by the vaccination programme, we simulated a 50% efficacy vaccine providing 10-years of protection in post-infection populations between 2027 and 2050 in India and China using a dynamic transmission model of M. tuberculosis. We investigated two mass vaccination strategies, both delivered every 10-years achieving 70% coverage: Vaccinating adults and adolescents (age ≥10y), or only the most efficient 10-year age subgroup (defined as greatest DALYs averted per vaccine given). We used country-specific thresholds for cost-effectiveness to estimate the maximum total cost (Cmax) a government should be willing to pay for each vaccination strategy. Adult/adolescent vaccination resulted in a Cmax of $21 billion (uncertainty interval [UI]: 16–27) in India, and $15B (UI:12–29) in China at willingness to pay thresholds of $264/DALY averted and $3650/DALY averted, respectively. Vaccinating the highest efficiency age group (India: 50–59y; China: 60–69y) resulted in a Cmax of $5B (UI:4–6) in India and $6B (UI:4–7) in China. Mass vaccination against tuberculosis of all adults and adolescents, deemed cost-effective, will likely impose a substantial budgetary burden. Targeted tuberculosis vaccination, deemed cost-effective, may represent a more affordable approach.
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27
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White paper on challenges and opportunities for TB elimination with focus on COVID & Post-COVID era developed through scientific roundtable resolutions at NATCON 2020. Indian J Tuberc 2021; 68:134-138. [PMID: 33641834 PMCID: PMC7835111 DOI: 10.1016/j.ijtb.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 11/29/2022]
Abstract
A group of TB experts with vast clinical and epidemiological experience were drawn from a pool of doctors, epidemiologists and scientists participating in NATCON 2020 Conference in a closed-door session to discuss, highlight, and prioritize key resolutions that are most pertinent at present to eliminate TB from India and other developing countries in the Covid and post-COVID era. These Scientific experts were non-industry persons who met on 17th December, 2020 and used the prevailing scientific literature along with 2019 Joint Monitoring Mission document as a starting point of the discussion on this specific topic to build an agreement upon the resolutions. After the meeting on the virtual platform, all the attending doctors gave a set of recommendations on rebuilding TB Elimination programme in the Covid and Post-Covid era. Focused scientific roundtable discussion on rebuilding TB Elimination Post-Covid. Develop actionable recommendations for the scientific community and the government leadership to consider in moving forward. To prioritize the recommendations in the categories of Build-Prevent-Detect-Treat.
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28
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Weerasuriya CK, Harris RC, McQuaid CF, Bozzani F, Ruan Y, Li R, Li T, Rade K, Rao R, Ginsberg AM, Gomez GB, White RG. The epidemiologic impact and cost-effectiveness of new tuberculosis vaccines on multidrug-resistant tuberculosis in India and China. BMC Med 2021; 19:60. [PMID: 33632218 PMCID: PMC7908776 DOI: 10.1186/s12916-021-01932-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Despite recent advances through the development pipeline, how novel tuberculosis (TB) vaccines might affect rifampicin-resistant and multidrug-resistant tuberculosis (RR/MDR-TB) is unknown. We investigated the epidemiologic impact, cost-effectiveness, and budget impact of hypothetical novel prophylactic prevention of disease TB vaccines on RR/MDR-TB in China and India. METHODS We constructed a deterministic, compartmental, age-, drug-resistance- and treatment history-stratified dynamic transmission model of tuberculosis. We introduced novel vaccines from 2027, with post- (PSI) or both pre- and post-infection (P&PI) efficacy, conferring 10 years of protection, with 50% efficacy. We measured vaccine cost-effectiveness over 2027-2050 as USD/DALY averted-against 1-times GDP/capita, and two healthcare opportunity cost-based (HCOC), thresholds. We carried out scenario analyses. RESULTS By 2050, the P&PI vaccine reduced RR/MDR-TB incidence rate by 71% (UI: 69-72) and 72% (UI: 70-74), and the PSI vaccine by 31% (UI: 30-32) and 44% (UI: 42-47) in China and India, respectively. In India, we found both USD 10 P&PI and PSI vaccines cost-effective at the 1-times GDP and upper HCOC thresholds and P&PI vaccines cost-effective at the lower HCOC threshold. In China, both vaccines were cost-effective at the 1-times GDP threshold. P&PI vaccine remained cost-effective at the lower HCOC threshold with 49% probability and PSI vaccines at the upper HCOC threshold with 21% probability. The P&PI vaccine was predicted to avert 0.9 million (UI: 0.8-1.1) and 1.1 million (UI: 0.9-1.4) second-line therapy regimens in China and India between 2027 and 2050, respectively. CONCLUSIONS Novel TB vaccination is likely to substantially reduce the future burden of RR/MDR-TB, while averting the need for second-line therapy. Vaccination may be cost-effective depending on vaccine characteristics and setting.
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Affiliation(s)
- Chathika K Weerasuriya
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, UK.
| | - Rebecca C Harris
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, UK.,Currently employed at Sanofi Pasteur, Singapore, Singapore
| | - C Finn McQuaid
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Fiammetta Bozzani
- Department of Global Health and Development, Faculty of Public Health & Policy, London School of Hygiene and Tropical Medicine, London, UK
| | - Yunzhou Ruan
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | - Renzhong Li
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | - Tao Li
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | | | - Raghuram Rao
- National Tuberculosis Elimination Programme, New Delhi, India
| | - Ann M Ginsberg
- International AIDS Vaccine Initiative, New York, USA.,Current Affiliation: Bill and Melinda Gates Foundation, Washington DC, USA
| | - Gabriela B Gomez
- Department of Global Health and Development, Faculty of Public Health & Policy, London School of Hygiene and Tropical Medicine, London, UK.,Currently employed at Sanofi Pasteur, Lyon, France
| | - Richard G White
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, UK
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29
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Emery JC, Richards AS, Dale KD, McQuaid CF, White RG, Denholm JT, Houben RMGJ. Self-clearance of Mycobacterium tuberculosis infection: implications for lifetime risk and population at-risk of tuberculosis disease. Proc Biol Sci 2021; 288:20201635. [PMID: 33467995 PMCID: PMC7893269 DOI: 10.1098/rspb.2020.1635] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/30/2020] [Indexed: 01/13/2023] Open
Abstract
Background: it is widely assumed that individuals with Mycobacterium tuberculosis (Mtb) infection remain at lifelong risk of tuberculosis (TB) disease. However, there is substantial evidence that self-clearance of Mtb infection can occur. We infer a curve of self-clearance by time since infection and explore its implications for TB epidemiology. Methods and findings: data for self-clearance were inferred using post-mortem and tuberculin-skin-test reversion studies. A cohort model allowing for self-clearance was fitted in a Bayesian framework before estimating the lifetime risk of TB disease and the population infected with Mtb in India, China and Japan in 2019. We estimated that 24.4% (17.8-32.6%, 95% uncertainty interval (UI)) of individuals self-clear within 10 years of infection, and 73.1% (64.6-81.7%) over a lifetime. The lifetime risk of TB disease was 17.0% (10.9-22.5%), compared to 12.6% (10.1-15.0%) assuming lifelong infection. The population at risk of TB disease in India, China and Japan was 35-80% (95% UI) smaller in the self-clearance scenario. Conclusions: the population with a viable Mtb infection may be markedly smaller than generally assumed, with such individuals at greater risk of TB disease. The ability to identify these individuals could dramatically improve the targeting of preventive programmes and inform TB vaccine development, bringing TB elimination within reach of feasibility.
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Affiliation(s)
- Jon C. Emery
- TB Modelling Group, TB Centre and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Alexandra S. Richards
- TB Modelling Group, TB Centre and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Katie D. Dale
- Victorian Tuberculosis Program, Melbourne Health, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
| | - C. Finn McQuaid
- TB Modelling Group, TB Centre and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Richard G. White
- TB Modelling Group, TB Centre and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Justin T. Denholm
- Victorian Tuberculosis Program, Melbourne Health, Melbourne, Victoria, Australia
| | - Rein M. G. J. Houben
- TB Modelling Group, TB Centre and Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
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30
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Flores-Valdez MA, Segura-Cerda CA. Preclinical evaluation of tuberculosis vaccine candidates: Is it time to harmonize study design and readouts for prioritizing their development? Vaccine 2020; 39:173-175. [PMID: 33334615 DOI: 10.1016/j.vaccine.2020.11.073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/23/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Affiliation(s)
- Mario Alberto Flores-Valdez
- Centro de Investigación y Asistencia en Tecnología y diseño del Estado de Jalisco, A. C., Biotecnología Médica y Farmacéutica, Av. Normalistas 800, Col. Colinas de la Normal, 44270 Guadalajara, Jalisco, Mexico.
| | - Cristian Alfredo Segura-Cerda
- Centro de Investigación y Asistencia en Tecnología y diseño del Estado de Jalisco, A.C., Biotecnología Médica y Farmacéutica, Av. Normalistas 800, Col. Colinas de la Normal, Guadalajara, Jalisco 44270, Mexico
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31
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Weerasuriya CK, Clark RA, White RG, Harris RC. New tuberculosis vaccines: advances in clinical development and modelling. J Intern Med 2020; 288:661-681. [PMID: 33128834 DOI: 10.1111/joim.13197] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/02/2020] [Accepted: 10/20/2020] [Indexed: 01/04/2023]
Abstract
Tuberculosis remains a major source of morbidity and mortality worldwide, with 10 million cases and 1.5 million deaths in 2018. Achieving 'End TB' prevention and care goals by 2035 will likely require a new tuberculosis vaccine. The tuberculosis vaccine development pipeline has seen encouraging progress; however, questions around their population impact and implementation remain. Mathematical modelling investigates these questions to inform vaccine development and deployment strategies. We provide an update on the current vaccine development pipeline, and a systematic literature review of mathematical modelling of the epidemiological impact of new tuberculosis vaccines. Fourteen prophylactic tuberculosis vaccine candidates are currently in clinical trials. Two candidates have shown promise in phase II proof-of-concept efficacy trials: M72/AS01E demonstrated 49.7% (95% CI; 2.1, 74.2) protection against tuberculosis disease, and BCG revaccination demonstrated 45.4% (95% CI; 6.4, 68.1) protection against sustained Mycobacterium tuberculosis infection. Since the last modelling review, new studies have investigated the epidemiological impact of differential vaccine characteristics, age targeting and spatial/risk group targeting. Critical research priorities for M72/AS01E include completing the currently in-design trial, powered to improve the precision of efficacy estimates, include uninfected populations and further assess safety and immunogenicity in HIV-infected people. For BCG revaccination, the priority is completing the ongoing confirmation of efficacy trial. Critical modelling gaps remain on the full value proposition of vaccines, comparisons with other interventions and more realistic implementation strategies. Using carefully designed trials and modelling, we must prepare for success, to ensure that new vaccines will be promptly received by those most in need.
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Affiliation(s)
- C K Weerasuriya
- From the, TB Modelling Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - R A Clark
- From the, TB Modelling Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - R G White
- From the, TB Modelling Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - R C Harris
- From the, TB Modelling Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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32
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Harris RC, Sumner T, Knight GM, Zhang H, White RG. Potential impact of tuberculosis vaccines in China, South Africa, and India. Sci Transl Med 2020; 12:eaax4607. [PMID: 33028708 DOI: 10.1126/scitranslmed.aax4607] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 11/12/2019] [Accepted: 09/16/2020] [Indexed: 12/11/2022]
Abstract
More effective tuberculosis vaccines are needed to help reach World Health Organization tuberculosis elimination goals. Insufficient evidence exists on the potential impact of future tuberculosis vaccines with varying characteristics and in different epidemiological settings. To inform vaccine development decision making, we modeled the impact of hypothetical tuberculosis vaccines in three high-burden countries. We calibrated Mycobacterium tuberculosis (M.tb) transmission models to age-stratified demographic and epidemiological data from China, South Africa, and India. We varied vaccine efficacy to prevent infection or disease, effective in persons M.tb uninfected or infected, and duration of protection. We modeled routine early-adolescent vaccination and 10-yearly mass campaigns from 2025. We estimated median percentage population-level tuberculosis incidence rate reduction (IRR) in 2050 compared to a no new vaccine scenario. In all settings, results suggested vaccines preventing disease in M.tb-infected populations would have greatest impact by 2050 (10-year, 70% efficacy against disease, IRR 51%, 52%, and 54% in China, South Africa, and India, respectively). Vaccines preventing reinfection delivered lower potential impact (IRR 1, 12, and 17%). Intermediate impact was predicted for vaccines effective only in uninfected populations, if preventing infection (IRR 21, 37, and 50%) or disease (IRR 19, 36, and 51%), with greater impact in higher-transmission settings. Tuberculosis vaccines have the potential to deliver substantial population-level impact. For prioritizing impact by 2050, vaccine development should focus on preventing disease in M.tb-infected populations. Preventing infection or disease in uninfected populations may be useful in higher transmission settings. As vaccine impact depended on epidemiology, different development strategies may be required.
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Affiliation(s)
- Rebecca C Harris
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | - Tom Sumner
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Gwenan M Knight
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Hui Zhang
- Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Richard G White
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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33
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Scriba TJ, Netea MG, Ginsberg AM. Key recent advances in TB vaccine development and understanding of protective immune responses against Mycobacterium tuberculosis. Semin Immunol 2020; 50:101431. [PMID: 33279383 PMCID: PMC7786643 DOI: 10.1016/j.smim.2020.101431] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/02/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022]
Abstract
Tuberculosis is the leading infectious disease killer globally due to a single pathogen. Despite wide deployment of standard drug regimens, modern diagnostics and a vaccine (bacille Calmette Guerin, BCG), the global tuberculosis epidemic is inadequately controlled. Novel, effective vaccine(s) are a crucial element of the World Health Organization End TB Strategy. TB vaccine research and development has recently been catalysed by several factors, including a revised strategy focused first on preventing pulmonary TB in adolescents and adults who are the main source of transmission, and encouraging evaluations of novel efficacy endpoints. Renewed enthusiasm for TB vaccine research has also been stimulated by recent preclinical and clinical advancements. These include new insights into underlying protective immune responses, including potential roles for 'trained' innate immunity and Th1/Th17 CD4+ (and CD8+) T cells. The field has been further reinvigorated by two positive proof of concept efficacy trials: one evaluating a potential new use of BCG in preventing high risk populations from sustained Mycobacterium tuberculosis infection and the second evaluating a novel, adjuvanted, recombinant protein vaccine candidate (M72/AS01E) for prevention of disease in adults already infected. Fourteen additional candidates are currently in various phases of clinical evaluation and multiple approaches to next generation vaccines are in discovery and preclinical development. The two positive efficacy trials and recent studies in nonhuman primates have enabled the first opportunities to discover candidate vaccine-induced correlates of protection, an effort being undertaken by a broad research consortium.
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Affiliation(s)
- Thomas J Scriba
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine and Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa.
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, Geert Grooteplein 8, 6525 GA Nijmegen, the Netherlands; Department of Genomics & Immunoregulation, Life and Medical Sciences Institute (LIMES), University of Bonn, Germany.
| | - Ann M Ginsberg
- Bill & Melinda Gates Foundation, Division of Global Health, Washington DC, United States.
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34
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McQuaid CF, McCreesh N, Read JM, Sumner T, Houben RMGJ, White RG, Harris RC. The potential impact of COVID-19-related disruption on tuberculosis burden. Eur Respir J 2020; 56:2001718. [PMID: 32513784 PMCID: PMC7278504 DOI: 10.1183/13993003.01718-2020] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 05/30/2020] [Indexed: 12/13/2022]
Abstract
Before the coronavirus disease 2019 (COVID-19) pandemic, over 4000 people were dying from tuberculosis (TB) every day [1]. As with past emergencies [2], the impact of COVID-19 on TB outcomes is a serious cause for concern [3] but is currently unknown. Health system overload, due to high numbers of COVID-19 cases, as well as interventions necessary to limit the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), could result in severe reductions in health service availability and access for the detection and treatment of TB cases [4]. However, physical distancing interventions could also limit Mycobacterium tuberculosis transmission outside of households, where most transmission occurs [5]. This has not been adequately explored in concurrent work [6–8], and it is currently unclear whether social distancing could compensate for disruptions in TB services, and what the impact of these combined COVID-19 disruption effects on TB burden is likely to be. Any benefit of social distancing on TB deaths is likely to be outweighed by health service disruption. As such, it is crucially important to maintain and strengthen TB-related health services during, and after, the COVID-19 pandemic. https://bit.ly/30aWZnp
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Affiliation(s)
- C Finn McQuaid
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Nicky McCreesh
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Jonathan M Read
- Center for Health Informatics Computing and Statistics, Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Tom Sumner
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Rein M G J Houben
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Richard G White
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Rebecca C Harris
- TB Modelling Group, TB Centre, and Centre for Mathematical Modelling of Infectious Diseases, Dept of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Sanofi Pasteur, Singapore
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35
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Liu SY, Shen MW, Bi YJ. Global asymptotic behavior for mixed vaccination strategy in a delayed epidemic model with interim-immune. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2020; 17:3601-3617. [PMID: 32987546 DOI: 10.3934/mbe.2020203] [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: 06/11/2023]
Abstract
Vaccination strategy is considered as the most cost-effective intervention measure for controlling diseases. It will strengthen the immunity and reduce the risks of infections. In this paper, a new delayed epidemic model with interim-immune and mixed vaccination strategy is studied. The diseasefree periodic solution is obtained by twice stroboscopic mapping and the corresponding dynamical behavior is analyzed. We determine a threshold parameter R1, the disease-free periodic solution is proved to be global attractive if R1 < 1. We also establish a threshold parameter R2 for the permanence of the model, i.e., if R2 > 1, the infectious disease will exist persistently. Then, we provide numerical simulations to illustrate our theoretical results intuitively. In particular, a practical application for newtype TB vaccine under mixed vaccination strategy is presented, based on the proposed theory and the data reported by NBSC. The mixed vaccination strategy can achieve the End TB goal formulated by WHO in limited time. Our study will help public health agency to design mixed control strategy which can reduce the burden of infectious diseases.
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Affiliation(s)
- Si Yu Liu
- School of Public Health, Jilin University, Changchun, Jilin, 130021, China
| | - Ming Wang Shen
- China-Australia Joint Research Center for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
| | - Ying Jie Bi
- School of Mathematics, Jilin University, Changchun, Jilin, 130012, China
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36
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Abstract
Exciting clinical results from 2 clinical TB vaccine trials were published in 2018. These, plus promising preclinical candidates form a healthy pipeline of potential vaccines against the leading cause of death from a single infectious agent. The only licensed vaccine, the BCG, continues to be an important tool in protecting against severe forms of TB in children, but has not stopped the diseases causing 1.3 million deaths per year. This review provides an overview of the current TB vaccine pipeline, highlighting recent findings, describes work relating to epidemiologic impact of vaccines, and discusses the future of TB vaccine development.
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Affiliation(s)
- Lisa Stockdale
- Department of Paediatrics, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre and Oxford University Hospitals NHS Foundation Trust, Oxford, UK. https://twitter.com/LisaStockdale
| | - Helen Fletcher
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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37
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Hatherill M, White RG, Hawn TR. Clinical Development of New TB Vaccines: Recent Advances and Next Steps. Front Microbiol 2020; 10:3154. [PMID: 32082273 PMCID: PMC7002896 DOI: 10.3389/fmicb.2019.03154] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/30/2019] [Indexed: 11/28/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) kills more people worldwide than any single infectious pathogen, yet the only vaccine licensed against tuberculosis, Bacille Calmette Guerin (BCG) is approaching its centenary. Two recent advances in clinical tuberculosis vaccine development have invigorated the field. BCG revaccination of interferon-gamma release assay (IGRA) negative adolescents provided 45% protection against sustained Mtb infection defined by IGRA conversion; and the protein-subunit vaccine M72/AS01E provided 50% protection against progression from Mtb infection to tuberculosis disease in IGRA-positive adults. These findings provide encouraging evidence for pre-exposure and post-exposure approaches to vaccination against tuberculosis, both of which may be necessary to rapidly interrupt the cycle of Mtb transmission and sustain long-term impact on global tuberculosis control. New trials are needed to demonstrate efficacy of M72/AS01E with greater precision, in a wider age range, in diverse epidemic settings, and in populations that include Mtb-uninfected and HIV-infected persons. Modeling the impact of mass campaigns with M72/AS01E and other fast-follower vaccine candidates will be crucial to make the use case and demonstrate public health value for TB endemic countries. The size and scope of the next generation of efficacy trials, and the need to expand and accelerate the existing clinical development pipeline, will require public and private consortium funding and concerted political will.
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Affiliation(s)
- Mark Hatherill
- South African Tuberculosis Vaccine Initiative (SATVI), Division of Immunology, Department of Pathology, Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Richard G White
- TB Modelling Group, TB Centre - Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Thomas R Hawn
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, United States
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38
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Xie Y, Han J, Yu W, Wu J, Li X, Chen H. Survival Analysis of Risk Factors for Mortality in a Cohort of Patients with Tuberculosis. Can Respir J 2020; 2020:1654653. [PMID: 32963642 PMCID: PMC7492936 DOI: 10.1155/2020/1654653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/27/2020] [Accepted: 08/25/2020] [Indexed: 02/05/2023] Open
Abstract
Identify the treatment effects and risk factors for mortality in patients with pulmonary tuberculosis receiving antituberculosis treatment under the Directly Observed Treatment Short-Course (DOTS) program to reduce the mortality rate of tuberculosis. A retrospective cohort analysis was conducted on the outcomes of antituberculosis treatment of 7,032 patients with tuberculosis in the DOTS program, in the Tuberculosis Management Information System from 2014 to 2017 in Tianjin, China. The Kaplan-Meier method and multifactor Cox proportional risk regression model were used to analyze the risk factors for mortality during antituberculosis treatment under DOTS. The success rate of antituberculosis treatment was 90.24% and the mortality rate was 4.56% among 7,032 cases of tuberculosis in Tianjin. Cox regression analysis showed that advanced age, male sex, human immunodeficiency virus (HIV) positivity, first sputum positivity, retreated tuberculosis, and a delayed visit (≥14 days) were risk factors for mortality in patients with pulmonary tuberculosis receiving antituberculosis treatment under DOTS. The treatment effects in patients with pulmonary tuberculosis during antituberculosis treatment under DOTS were positive in Tianjin. Advanced age, male sex, HIV positivity, first sputum positivity, retreated tuberculosis, and a delayed visit (≥14 days) increased the risk for mortality during antituberculosis treatment.
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Affiliation(s)
- Yi Xie
- 1Department of Prevention, Haihe Hospital, Tianjin University, Tianjin, China
- 2Tianjin Key Laboratory of Lung Regenerative Medicine, Tianjin, China
| | - Jing Han
- 3Department of Medical Administration, Haihe Hospital, Tianjin University, Tianjin, China
| | - Weili Yu
- 1Department of Prevention, Haihe Hospital, Tianjin University, Tianjin, China
| | - Junping Wu
- 2Tianjin Key Laboratory of Lung Regenerative Medicine, Tianjin, China
- 4Department of Basic Medicine, Tianjin Institute of Respiratory Diseases, Tianjin, China
| | - Xue Li
- 2Tianjin Key Laboratory of Lung Regenerative Medicine, Tianjin, China
- 4Department of Basic Medicine, Tianjin Institute of Respiratory Diseases, Tianjin, China
| | - Huaiyong Chen
- 2Tianjin Key Laboratory of Lung Regenerative Medicine, Tianjin, China
- 4Department of Basic Medicine, Tianjin Institute of Respiratory Diseases, Tianjin, China
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39
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Forecasting the impact of population ageing on tuberculosis incidence. PLoS One 2019; 14:e0222937. [PMID: 31550293 PMCID: PMC6759178 DOI: 10.1371/journal.pone.0222937] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/10/2019] [Indexed: 12/14/2022] Open
Abstract
Background Tuberculosis (TB) disease reactivates from distant latent infection or recent (re)infection. Progression risks increase with age. Across the World Health Organisation Western Pacific region, many populations are ageing and have the highest per capita TB incidence rates in older age groups. However, methods for analysing age-specific TB incidence and forecasting epidemic trends while accounting for demographic change remain limited. Methods We applied the Lee-Carter models, which were originally developed for mortality modelling, to model the temporal trends in age-specific TB incidence data from 2005 to 2018 in Taiwan. Females and males were modelled separately. We combined our demographic forecasts, and age-specific TB incidence forecasts to project TB incidence until 2035. We compared TB incidence projections with demography fixed in 2018 to projections accounting for demographic change. Results Our models quantified increasing incidence rates with age and declining temporal trends. By 2035, the forecast suggests that the TB incidence rate in Taiwan will decrease by 54% (95% Prediction Interval (PI): 45%-59%) compared to 2015, while most age-specific incidence rates will reduce by more than 60%. In 2035, adults aged 65 and above will make up 78% of incident TB cases. Forecast TB incidence in 2035 accounting for demographic change will be 39% (95% PI: 36%-42%) higher than without population ageing. Conclusions Age-specific incidence forecasts coupled with demographic forecasts can inform the impact of population ageing on TB epidemics. The TB control programme in Taiwan should develop plans specific to older age groups and their care needs.
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40
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Abstract
Johan Vekemans, Katherine O'Brien, and Jeremy Farrar discuss recent breakthroughs in the search for a highly effective tuberculosis vaccine.
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Affiliation(s)
- Johan Vekemans
- World Health Organization, Initiative for Vaccine Research, Geneva, Switzerland
| | - Katherine L O'Brien
- World Health Organization, Initiative for Vaccine Research, Geneva, Switzerland
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41
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Flores-Valdez MA. New potential biomarkers to assess efficacy of protection afforded by vaccine candidates against tuberculosis. Clin Microbiol Infect 2019; 25:656-658. [PMID: 30797061 DOI: 10.1016/j.cmi.2019.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/21/2019] [Accepted: 02/10/2019] [Indexed: 12/25/2022]
Affiliation(s)
- M A Flores-Valdez
- Centro de Investigación y Asistencia en Tecnología y diseño del Estado de Jalisco, A.C. Biotecnología Médica y Farmacéutica, Guadalajara, Jalisco, Mexico.
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42
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Wang Y, Wang W. Importance of tuberculosis vaccination targeting older people in China. THE LANCET GLOBAL HEALTH 2019; 7:e165-e166. [DOI: 10.1016/s2214-109x(18)30480-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 10/11/2018] [Indexed: 11/24/2022] Open
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