The Experts below are selected from a list of 118368 Experts worldwide ranked by ideXlab platform
Peter J White - One of the best experts on this subject based on the ideXlab platform.
-
Using molecular testing and whole-genome sequencing for tuberculosis diagnosis in a low-burden setting: a cost-effectiveness analysis using Transmission-Dynamic modelling.
Thorax, 2021Co-Authors: Tendai Mugwagwa, Ibrahim Abubakar, Peter J WhiteAbstract:Background Despite progress in TB control in low-burden countries like England and Wales, there are still diagnostic delays. Molecular testing and/or whole-genome sequencing (WGS) provide more rapid diagnosis but their cost-effectiveness is relatively unexplored in low-burden settings. Methods An integrated Transmission-Dynamic health economic model is used to assess the cost-effectiveness of using WGS to replace culture-based drug-sensitivity testing, versus using molecular testing versus combined use of WGS and molecular testing, for routine TB diagnosis. The model accounts for the effects of faster appropriate treatment in reducing Transmission, benefiting health and reducing future treatment costs. Cost-effectiveness is assessed using incremental net benefit (INB) over a 10-year horizon with a quality-adjusted life-year valued at £20 000, and discounting at 3.5% per year. Results WGS shortens the time to drug sensitivity testing and treatment modification where necessary, reducing treatment and hospitalisation costs, with an INB of £7.1 million. Molecular testing shortens the time to TB diagnosis and treatment. Initially, this causes an increase in annual costs of treatment, but averting Transmissions and future active TB disease subsequently, resulting in cost savings and health benefits to achieve an INB of £8.6 million (GeneXpert MTB/RIF) or £11.1 million (Xpert-Ultra). Combined use of Xpert-Ultra and WGS is the optimal strategy we consider, with an INB of £16.5 million. Conclusion Routine use of WGS or molecular testing is cost-effective in a low-burden setting, and combined use is the most cost-effective option. Adoption of these technologies can help low-burden countries meet the WHO End TB Strategy milestones, particularly the UK, which still has relatively high TB rates.
-
Comparing different technologies for active TB case-finding among the homeless: a Transmission-Dynamic modelling study.
Scientific reports, 2018Co-Authors: Tendai Mugwagwa, Helen R. Stagg, Ibrahim Abubakar, Peter J WhiteAbstract:Homeless persons have elevated risk of tuberculosis (TB) and are under-served by conventional health services. Approaches to active case-finding (ACF) and treatment tailored to their needs are required. A Transmission-Dynamic model was developed to assess the effectiveness and efficiency of screening with mobile Chest X-ray, GeneXpert, or both. Effectiveness of ACF depends upon the prevalence of infection in the population (which determines screening ‘yield’), patient willingness to wait for GeneXpert results, and treatment adherence. ACF is efficient when TB prevalence exceeds 78/100,000 and 46% of drug sensitive TB cases and 33% of multi-drug resistant TB cases complete treatment. This threshold increases to 92/100,000 if additional post-ACF enhanced case management (ECM) increases treatment completion to 85%. Generally, the most efficient option is one-step screening of all patients with GeneXpert, but if too many patients (>27% without ECM, >19% with ECM) are unwilling to wait the 90 minutes required then two-step screening using chest X-ray (which is rapid) followed by GeneXpert for confirmation of TB is the most efficient option. Targeted ACF and support services benefit health through early successful treatment and averting TB Transmission and disease. The optimal strategy is setting-specific, requiring careful consideration of patients’ needs regarding testing and treatment.
-
Should we screen for the sexually-transmitted infection Mycoplasma genitalium? Evidence synthesis using a Transmission-Dynamic model.
Scientific reports, 2017Co-Authors: Ruthie Birger, John Saunders, Claudia Estcourt, Andrew J Sutton, Catherine H Mercer, Tracy E Roberts, Peter J WhiteAbstract:There is increasing concern about Mycoplasma genitalium as a cause of urethritis, cervicitis, pelvic inflammatory disease (PID), infertility and ectopic pregnancy. Commercial nucleic acid amplification tests (NAATs) are becoming available, and their use in screening for M. genitalium has been advocated, but M. genitalium's natural history is poorly-understood, making screening's effectiveness unclear. We used a Transmission-Dynamic compartmental model to synthesise evidence from surveillance data and epidemiological and behavioural studies to better understand M. genitalium's natural history, and then examined the effects of implementing NAAT testing. Introducing NAAT testing initially increases diagnoses, by finding a larger proportion of infections; subsequently the diagnosis rate falls, due to reduced incidence. Testing only symptomatic patients finds relatively little infection in women, as a large proportion is asymptomatic. Testing both symptomatic and asymptomatic patients has a much larger impact and reduces cumulative PID incidence in women due to M. genitalium by 31.1% (95% range:13.0%-52.0%) over 20 years. However, there is important uncertainty in M. genitalium's natural history parameters, leading to uncertainty in the absolute reduction in PID and sequelae. Empirical work is required to improve understanding of key aspects of M. genitalium's natural history before it will be possible to determine the effectiveness of screening.
-
P09.11 Should we screen for mycoplasma genitalium? evidence synthesis using a Transmission-Dynamic model
Sexually Transmitted Infections, 2015Co-Authors: Ruthie Birger, John Saunders, Claudia Estcourt, Andrew J Sutton, Ch Mercer, T Roberts, Peter J WhiteAbstract:Introduction There is increasing concern about Mycoplasma genitalium as a cause of urethritis, cervicitis, PID, infertility and ectopic pregnancy. Currently there is no licensed test specific for M. genitalium in the UK, where urethral smear microscopy is recommended in GUM clinics, for symptomatic men only. NAATs testing has been advocated, particularly to detect asymptomatic infection. However, M. genitalium ’s natural history is poorly-understood, making the impact and cost-effectiveness of screening unclear. Methods We used a Transmission-Dynamic model to synthesise evidence from epidemiological and behavioural studies, and surveillance data for Non-Chlamydial, Non-Gonococcal Urethritis (NCNGU), to better-understand the natural history of M. genitalium . The model is stratified by sex, and incorporates heterogeneous sexual behaviour, symptomatic and asymptomatic infection; PID; care-seeking due to symptoms and routine screening; and treatment failure. We fitted to national surveillance data, (allowing for uncertainty in studies measuring the amount of NCNGU caused by M. genitalium ). We examined the effects of implementing NAAT testing for both sexes in GUM and GP settings. Results Introducing NAAT testing for all men (asymptomatic and symptomatic, in GPs and GUM) detects much more infection in men and treatment reduces Transmission to women, whilst testing of women reduces prevalence in women and incidence in men. Introducing NAAT testing for both sexes reduces cumulative PID incidence over 20 years by 13.1%(IQR:9.6%–18.3%). However, there is important uncertainty in M. genitalium ’s natural history parameters, leading to uncertainty in the absolute reduction in PID and other sequelae. Particularly important are the proportion of infections that are symptomatic in men and women; duration of untreated infection; and incidence of PID, infertility and ectopic pregnancy attributable to M. genitalium . Conclusion Further empirical work is required to improve understanding of the key aspects of M. genitalium ’s natural history which we have identified before it will be possible to determine if screening is cost-effective. Disclosure of interest statement This presentation reports independent research commissioned by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (RP-PG-0707–10208). In addition, PJW thanks the UK Medical Research Council for Centre funding (grant MR/K010174/1) and also thanks the UK National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Modelling Methodology at Imperial College London in partnership with Public Health England (PHE) for funding (grant HPRU-2012–10080). The views expressed in this paper are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health, or Public Health England. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We have no conflicts of interest.
Joshua A Salomon - One of the best experts on this subject based on the ideXlab platform.
-
prospects for tuberculosis elimination in the united states results of a Transmission Dynamic model
American Journal of Epidemiology, 2018Co-Authors: Nicolas A. Menzies, Ted Cohen, Reza Yaesoubi, Andrew N Hill, Kara Galer, Emory E Wolf, Suzanne M Marks, Joshua A SalomonAbstract:: We estimated long-term tuberculosis (TB) trends in the US population and assessed prospects for TB elimination. We used a detailed simulation model allowing for changes in TB Transmission, immigration, and other TB risk determinants. Five hypothetical scenarios were evaluated from 2017 to 2100: 1) maintain current TB prevention and treatment activities (base case); 2) provision of latent TB infection testing and treatment for new legal immigrants; 3) increased uptake of latent TB infection screening and treatment among high-risk populations, including a 3-month isoniazid-rifapentine regimen; 4) improved TB case detection; and 5) improved TB treatment quality. Under the base case, we estimate that by 2050, TB incidence will decline to 14 cases per million, a 52% (95% posterior interval (PI): 35, 67) reduction from 2016, and 82% (95% posterior interval: 78, 86) of incident TB will be among persons born outside of the United States. Intensified TB control could reduce incidence by 77% (95% posterior interval: 66, 85) by 2050. We predict TB may be eliminated in US-born but not non-US-born persons by 2100. Results were sensitive to numbers of people entering the United States with latent or active TB, and were robust to alternative interpretations of epidemiologic evidence. TB elimination in the United States remains a distant goal; however, strengthening TB prevention and treatment could produce important health benefits.
Ted Cohen - One of the best experts on this subject based on the ideXlab platform.
-
The positive externalities of migrant-based TB control strategy in a Chinese urban population with internal migration: a Transmission-Dynamic modeling study
BMC Medicine, 2021Co-Authors: Chongguang Yang, Jian Kang, Xiaoqin Guo, Xin Shen, Ted Cohen, Nicolas A. MenziesAbstract:Abstract Background Large-scale rural-to-urban migration has changed the epidemiology of tuberculosis (TB) in large Chinese cities. We estimated the contribution of TB importation, reactivation of latent infection, and local Transmission to new TB cases in Shanghai, and compared the potential impact of intervention options. Methods We developed a Transmission Dynamic model of TB for Songjiang District, Shanghai, which has experienced high migration over the past 25 years. We calibrated the model to local demographic data, TB notifications, and molecular epidemiologic studies. We estimated epidemiological drivers as well as future outcomes of current TB policies and compared this base-case scenario with scenarios describing additional targeted interventions focusing on migrants or vulnerable residents. Results The model captured key demographic and epidemiological features of TB among migrant and resident populations in Songjiang District, Shanghai. Between 2020 and 2035, we estimate that over 60% of TB cases will occur among migrants and that approximately 43% of these cases will result from recent infection. While TB incidence will decline under current policies, we estimate that additional interventions—including active screening and preventive treatment for migrants—could reduce TB incidence by an additional 20% by 2035. Conclusions Migrant-focused TB interventions could produce meaningful health benefits for migrants, as well as for young residents who receive indirect protection as a result of reduced TB Transmission in Shanghai. Further studies to measure cost-effectiveness are needed to evaluate the feasibility of these interventions in Shanghai and similar urban centers experiencing high migration volumes.
-
Accurate quantification of uncertainty in epidemic parameter estimates and predictions using stochastic compartmental models
Statistical methods in medical research, 2018Co-Authors: Christoph Zimmer, Ted Cohen, Sequoia I. Leuba, Reza YaesoubiAbstract:Stochastic Transmission Dynamic models are needed to quantify the uncertainty in estimates and predictions during outbreaks of infectious diseases. We previously developed a calibration method for ...
-
prospects for tuberculosis elimination in the united states results of a Transmission Dynamic model
American Journal of Epidemiology, 2018Co-Authors: Nicolas A. Menzies, Ted Cohen, Reza Yaesoubi, Andrew N Hill, Kara Galer, Emory E Wolf, Suzanne M Marks, Joshua A SalomonAbstract:: We estimated long-term tuberculosis (TB) trends in the US population and assessed prospects for TB elimination. We used a detailed simulation model allowing for changes in TB Transmission, immigration, and other TB risk determinants. Five hypothetical scenarios were evaluated from 2017 to 2100: 1) maintain current TB prevention and treatment activities (base case); 2) provision of latent TB infection testing and treatment for new legal immigrants; 3) increased uptake of latent TB infection screening and treatment among high-risk populations, including a 3-month isoniazid-rifapentine regimen; 4) improved TB case detection; and 5) improved TB treatment quality. Under the base case, we estimate that by 2050, TB incidence will decline to 14 cases per million, a 52% (95% posterior interval (PI): 35, 67) reduction from 2016, and 82% (95% posterior interval: 78, 86) of incident TB will be among persons born outside of the United States. Intensified TB control could reduce incidence by 77% (95% posterior interval: 66, 85) by 2050. We predict TB may be eliminated in US-born but not non-US-born persons by 2100. Results were sensitive to numbers of people entering the United States with latent or active TB, and were robust to alternative interpretations of epidemiologic evidence. TB elimination in the United States remains a distant goal; however, strengthening TB prevention and treatment could produce important health benefits.
-
the cost effectiveness of alternative vaccination strategies for polyvalent meningococcal vaccines in burkina faso a Transmission Dynamic modeling study
PLOS Medicine, 2018Co-Authors: Reza Yaesoubi, Caroline L Trotter, Caroline Colijn, Maziar Yaesoubi, Anais Colombini, Stephen C Resch, Paul A Kristiansen, Marc F Laforce, Ted CohenAbstract:Background The introduction of a conjugate vaccine for serogroup A Neisseria meningitidis has dramatically reduced disease in the African meningitis belt. In this context, important questions remain about the performance of different vaccine policies that target remaining serogroups. Here, we estimate the health impact and cost associated with several alternative vaccination policies in Burkina Faso. Methods and findings We developed and calibrated a mathematical model of meningococcal Transmission to project the disability-adjusted life years (DALYs) averted and costs associated with the current Base policy (serogroup A conjugate vaccination at 9 months, as part of the Expanded Program on Immunization [EPI], plus district-specific reactive vaccination campaigns using polyvalent meningococcal polysaccharide [PMP] vaccine in response to outbreaks) and three alternative policies: (1) Base Prime: novel polyvalent meningococcal conjugate (PMC) vaccine replaces the serogroup A conjugate in EPI and is also used in reactive campaigns; (2) Prevention 1: PMC used in EPI and in a nationwide catch-up campaign for 1–18-year-olds; and (3) Prevention 2: Prevention 1, except the nationwide campaign includes individuals up to 29 years old. Over a 30-year simulation period, Prevention 2 would avert 78% of the meningococcal cases (95% prediction interval: 63%–90%) expected under the Base policy if serogroup A is not replaced by remaining serogroups after elimination, and would avert 87% (77%–93%) of meningococcal cases if complete strain replacement occurs. Compared to the Base policy and at the PMC vaccine price of US$4 per dose, strategies that use PMC vaccine (i.e., Base Prime and Preventions 1 and 2) are expected to be cost saving if strain replacement occurs, and would cost US$51 (−US$236, US$490), US$188 (−US$97, US$626), and US$246 (−US$53, US$703) per DALY averted, respectively, if strain replacement does not occur. An important potential limitation of our study is the simplifying assumption that all circulating meningococcal serogroups can be aggregated into a single group; while this assumption is critical for model tractability, it would compromise the insights derived from our model if the effectiveness of the vaccine differs markedly between serogroups or if there are complex between-serogroup interactions that influence the frequency and magnitude of future meningitis epidemics. Conclusions Our results suggest that a vaccination strategy that includes a catch-up nationwide immunization campaign in young adults with a PMC vaccine and the addition of this new vaccine into EPI is cost-effective and would avert a substantial portion of meningococcal cases expected under the current World Health Organization–recommended strategy of reactive vaccination. This analysis is limited to Burkina Faso and assumes that polyvalent vaccines offer equal protection against all meningococcal serogroups; further studies are needed to evaluate the robustness of this assumption and applicability for other countries in the meningitis belt.
Nicolas A. Menzies - One of the best experts on this subject based on the ideXlab platform.
-
The positive externalities of migrant-based TB control strategy in a Chinese urban population with internal migration: a Transmission-Dynamic modeling study
BMC Medicine, 2021Co-Authors: Chongguang Yang, Jian Kang, Xiaoqin Guo, Xin Shen, Ted Cohen, Nicolas A. MenziesAbstract:Abstract Background Large-scale rural-to-urban migration has changed the epidemiology of tuberculosis (TB) in large Chinese cities. We estimated the contribution of TB importation, reactivation of latent infection, and local Transmission to new TB cases in Shanghai, and compared the potential impact of intervention options. Methods We developed a Transmission Dynamic model of TB for Songjiang District, Shanghai, which has experienced high migration over the past 25 years. We calibrated the model to local demographic data, TB notifications, and molecular epidemiologic studies. We estimated epidemiological drivers as well as future outcomes of current TB policies and compared this base-case scenario with scenarios describing additional targeted interventions focusing on migrants or vulnerable residents. Results The model captured key demographic and epidemiological features of TB among migrant and resident populations in Songjiang District, Shanghai. Between 2020 and 2035, we estimate that over 60% of TB cases will occur among migrants and that approximately 43% of these cases will result from recent infection. While TB incidence will decline under current policies, we estimate that additional interventions—including active screening and preventive treatment for migrants—could reduce TB incidence by an additional 20% by 2035. Conclusions Migrant-focused TB interventions could produce meaningful health benefits for migrants, as well as for young residents who receive indirect protection as a result of reduced TB Transmission in Shanghai. Further studies to measure cost-effectiveness are needed to evaluate the feasibility of these interventions in Shanghai and similar urban centers experiencing high migration volumes.
-
prospects for tuberculosis elimination in the united states results of a Transmission Dynamic model
American Journal of Epidemiology, 2018Co-Authors: Nicolas A. Menzies, Ted Cohen, Reza Yaesoubi, Andrew N Hill, Kara Galer, Emory E Wolf, Suzanne M Marks, Joshua A SalomonAbstract:: We estimated long-term tuberculosis (TB) trends in the US population and assessed prospects for TB elimination. We used a detailed simulation model allowing for changes in TB Transmission, immigration, and other TB risk determinants. Five hypothetical scenarios were evaluated from 2017 to 2100: 1) maintain current TB prevention and treatment activities (base case); 2) provision of latent TB infection testing and treatment for new legal immigrants; 3) increased uptake of latent TB infection screening and treatment among high-risk populations, including a 3-month isoniazid-rifapentine regimen; 4) improved TB case detection; and 5) improved TB treatment quality. Under the base case, we estimate that by 2050, TB incidence will decline to 14 cases per million, a 52% (95% posterior interval (PI): 35, 67) reduction from 2016, and 82% (95% posterior interval: 78, 86) of incident TB will be among persons born outside of the United States. Intensified TB control could reduce incidence by 77% (95% posterior interval: 66, 85) by 2050. We predict TB may be eliminated in US-born but not non-US-born persons by 2100. Results were sensitive to numbers of people entering the United States with latent or active TB, and were robust to alternative interpretations of epidemiologic evidence. TB elimination in the United States remains a distant goal; however, strengthening TB prevention and treatment could produce important health benefits.
Reza Yaesoubi - One of the best experts on this subject based on the ideXlab platform.
-
Accurate quantification of uncertainty in epidemic parameter estimates and predictions using stochastic compartmental models
Statistical methods in medical research, 2018Co-Authors: Christoph Zimmer, Ted Cohen, Sequoia I. Leuba, Reza YaesoubiAbstract:Stochastic Transmission Dynamic models are needed to quantify the uncertainty in estimates and predictions during outbreaks of infectious diseases. We previously developed a calibration method for ...
-
prospects for tuberculosis elimination in the united states results of a Transmission Dynamic model
American Journal of Epidemiology, 2018Co-Authors: Nicolas A. Menzies, Ted Cohen, Reza Yaesoubi, Andrew N Hill, Kara Galer, Emory E Wolf, Suzanne M Marks, Joshua A SalomonAbstract:: We estimated long-term tuberculosis (TB) trends in the US population and assessed prospects for TB elimination. We used a detailed simulation model allowing for changes in TB Transmission, immigration, and other TB risk determinants. Five hypothetical scenarios were evaluated from 2017 to 2100: 1) maintain current TB prevention and treatment activities (base case); 2) provision of latent TB infection testing and treatment for new legal immigrants; 3) increased uptake of latent TB infection screening and treatment among high-risk populations, including a 3-month isoniazid-rifapentine regimen; 4) improved TB case detection; and 5) improved TB treatment quality. Under the base case, we estimate that by 2050, TB incidence will decline to 14 cases per million, a 52% (95% posterior interval (PI): 35, 67) reduction from 2016, and 82% (95% posterior interval: 78, 86) of incident TB will be among persons born outside of the United States. Intensified TB control could reduce incidence by 77% (95% posterior interval: 66, 85) by 2050. We predict TB may be eliminated in US-born but not non-US-born persons by 2100. Results were sensitive to numbers of people entering the United States with latent or active TB, and were robust to alternative interpretations of epidemiologic evidence. TB elimination in the United States remains a distant goal; however, strengthening TB prevention and treatment could produce important health benefits.
-
the cost effectiveness of alternative vaccination strategies for polyvalent meningococcal vaccines in burkina faso a Transmission Dynamic modeling study
PLOS Medicine, 2018Co-Authors: Reza Yaesoubi, Caroline L Trotter, Caroline Colijn, Maziar Yaesoubi, Anais Colombini, Stephen C Resch, Paul A Kristiansen, Marc F Laforce, Ted CohenAbstract:Background The introduction of a conjugate vaccine for serogroup A Neisseria meningitidis has dramatically reduced disease in the African meningitis belt. In this context, important questions remain about the performance of different vaccine policies that target remaining serogroups. Here, we estimate the health impact and cost associated with several alternative vaccination policies in Burkina Faso. Methods and findings We developed and calibrated a mathematical model of meningococcal Transmission to project the disability-adjusted life years (DALYs) averted and costs associated with the current Base policy (serogroup A conjugate vaccination at 9 months, as part of the Expanded Program on Immunization [EPI], plus district-specific reactive vaccination campaigns using polyvalent meningococcal polysaccharide [PMP] vaccine in response to outbreaks) and three alternative policies: (1) Base Prime: novel polyvalent meningococcal conjugate (PMC) vaccine replaces the serogroup A conjugate in EPI and is also used in reactive campaigns; (2) Prevention 1: PMC used in EPI and in a nationwide catch-up campaign for 1–18-year-olds; and (3) Prevention 2: Prevention 1, except the nationwide campaign includes individuals up to 29 years old. Over a 30-year simulation period, Prevention 2 would avert 78% of the meningococcal cases (95% prediction interval: 63%–90%) expected under the Base policy if serogroup A is not replaced by remaining serogroups after elimination, and would avert 87% (77%–93%) of meningococcal cases if complete strain replacement occurs. Compared to the Base policy and at the PMC vaccine price of US$4 per dose, strategies that use PMC vaccine (i.e., Base Prime and Preventions 1 and 2) are expected to be cost saving if strain replacement occurs, and would cost US$51 (−US$236, US$490), US$188 (−US$97, US$626), and US$246 (−US$53, US$703) per DALY averted, respectively, if strain replacement does not occur. An important potential limitation of our study is the simplifying assumption that all circulating meningococcal serogroups can be aggregated into a single group; while this assumption is critical for model tractability, it would compromise the insights derived from our model if the effectiveness of the vaccine differs markedly between serogroups or if there are complex between-serogroup interactions that influence the frequency and magnitude of future meningitis epidemics. Conclusions Our results suggest that a vaccination strategy that includes a catch-up nationwide immunization campaign in young adults with a PMC vaccine and the addition of this new vaccine into EPI is cost-effective and would avert a substantial portion of meningococcal cases expected under the current World Health Organization–recommended strategy of reactive vaccination. This analysis is limited to Burkina Faso and assumes that polyvalent vaccines offer equal protection against all meningococcal serogroups; further studies are needed to evaluate the robustness of this assumption and applicability for other countries in the meningitis belt.
