Publications
220 results found
Mutono N, Basáñez M-G, James A, et al., 2024, Elimination of transmission of onchocerciasis (river blindness) with long-term ivermectin mass drug administration with or without vector control in sub-Saharan Africa: a systematic review and meta-analysis, The Lancet Global Health, Vol: 12, Pages: e771-e782, ISSN: 2214-109X
BACKGROUND: WHO has proposed elimination of transmission of onchocerciasis (river blindness) by 2030. More than 99% of cases of onchocerciasis are in sub-Saharan Africa. Vector control and mass drug administration of ivermectin have been the main interventions for many years, with varying success. We aimed to identify factors associated with elimination of onchocerciasis transmission in sub-Saharan Africa. METHODS: For this systematic review and meta-analysis we searched for published articles reporting epidemiological or entomological assessments of onchocerciasis transmission status in sub-Saharan Africa, with or without vector control. We searched MEDLINE, PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials, African Index Medicus, and Google Scholar databases for all articles published from database inception to Aug 19, 2023, without language restrictions. The search terms used were "onchocerciasis" AND "ivermectin" AND "mass drug administration". The three inclusion criteria were (1) focus or foci located in Africa, (2) reporting of elimination of transmission or at least 10 years of ivermectin mass drug administration in the focus or foci, and (3) inclusion of at least one of the following assessments: microfilarial prevalence, nodule prevalence, Ov16 antibody seroprevalence, and blackfly infectivity prevalence. Epidemiological modelling studies and reviews were excluded. Four reviewers (NM, AJ, AM, and TNK) extracted data in duplicate from the full-text articles using a data extraction tool developed in Excel with columns recording the data of interest to be extracted, and a column where important comments for each study could be highlighted. We did not request any individual-level data from authors. Foci were classified as achieving elimination of transmission, being close to elimination of transmission, or with ongoing transmission. We used mixed-effects meta-regression models to identify factors assoc
Davis EL, Hollingsworth TD, Keeling MJ, 2024, An analytically tractable, age-structured model of the impact of vector control on mosquito-transmitted infections., PLoS Comput Biol, Vol: 20
Vector control is a vital tool utilised by malaria control and elimination programmes worldwide, and as such it is important that we can accurately quantify the expected public health impact of these methods. There are very few previous models that consider vector-control-induced changes in the age-structure of the vector population and the resulting impact on transmission. We analytically derive the steady-state solution of a novel age-structured deterministic compartmental model describing the mosquito feeding cycle, with mosquito age represented discretely by parity-the number of cycles (or successful bloodmeals) completed. Our key model output comprises an explicit, analytically tractable solution that can be used to directly quantify key transmission statistics, such as the effective reproductive ratio under control, Rc, and investigate the age-structured impact of vector control. Application of this model reinforces current knowledge that adult-acting interventions, such as indoor residual spraying of insecticides (IRS) or long-lasting insecticidal nets (LLINs), can be highly effective at reducing transmission, due to the dual effects of repelling and killing mosquitoes. We also demonstrate how larval measures can be implemented in addition to adult-acting measures to reduce Rc and mitigate the impact of waning insecticidal efficacy, as well as how mid-ranges of LLIN coverage are likely to experience the largest effect of reduced net integrity on transmission. We conclude that whilst well-maintained adult-acting vector control measures are substantially more effective than larval-based interventions, incorporating larval control in existing LLIN or IRS programmes could substantially reduce transmission and help mitigate any waning effects of adult-acting measures.
Brady MA, Toubali E, Baker M, et al., 2023, Persons 'never treated' in mass drug administration for lymphatic filariasis: identifying programmatic and research needs from a series of research review meetings 2020-2021., Int Health
As neglected tropical disease programs rely on participation in rounds of mass drug administration (MDA), there is concern that individuals who have never been treated could contribute to ongoing transmission, posing a barrier to elimination. Previous research has suggested that the size and characteristics of the never-treated population may be important but have not been sufficiently explored. To address this critical knowledge gap, four meetings were held from December 2020 to May 2021 to compile expert knowledge on never treatment in lymphatic filariasis (LF) MDA programs. The meetings explored four questions: the number and proportion of people never treated, their sociodemographic characteristics, their infection status and the reasons why they were not treated. Meeting discussions noted key issues requiring further exploration, including how to standardize measurement of the never treated, adapt and use existing tools to capture never-treated data and ensure representation of never-treated people in data collection. Recognizing that patterns of never treatment are situation specific, participants noted measurement should be quick, inexpensive and focused on local solutions. Furthermore, programs should use existing data to generate mathematical models to understand what levels of never treatment may compromise LF elimination goals or trigger programmatic action.
Davis EL, Crump RE, Medley GF, et al., 2023, A modelling analysis of a new multi-stage pathway for classifying achievement of public health milestones for leprosy, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 378, ISSN: 0962-8436
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- Citations: 1
Forbes K, Basáñez M-G, Hollingsworth TD, et al., 2023, Introduction to the special issue: challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs, Philosophical Transactions of the Royal Society B: Biological Sciences, Vol: 378, Pages: 1-8, ISSN: 0962-8436
Twenty neglected tropical diseases (NTDs) are currently prioritised by the World Health Organization for eradication, elimination as a public health problem, elimination of transmission or control by 2030. This issue celebrates progress made since the 2012 London Declaration on NTDs and discusses challenges currently faced to achieve these goals. It comprises 14 contributions spanning NTDs tackled by intensified disease management to those addressed by preventive chemotherapy. Although COVID-19 negatively affected NTD programmes, it also served to spur new multisectoral approaches to strengthen school-based health systems. The issue highlights the needs to improve impact survey design, evaluate new diagnostics, understand the consequences of heterogeneous prevalence and human movement, the potential impact of alternative treatment strategies and the importance of zoonotic transmission. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
Clark J, Davis EL, Prada JM, et al., 2023, How correlations between treatment access and surveillance inclusion impact neglected tropical disease monitoring and evaluation-A simulated study., PLoS Negl Trop Dis, Vol: 17
Neglected tropical diseases (NTDs) largely impact marginalised communities living in tropical and subtropical regions. Mass drug administration is the leading intervention method for five NTDs; however, it is known that there is lack of access to treatment for some populations and demographic groups. It is also likely that those individuals without access to treatment are excluded from surveillance. It is important to consider the impacts of this on the overall success, and monitoring and evaluation (M&E) of intervention programmes. We use a detailed individual-based model of the infection dynamics of lymphatic filariasis to investigate the impact of excluded, untreated, and therefore unobserved groups on the true versus observed infection dynamics and subsequent intervention success. We simulate surveillance in four groups-the whole population eligible to receive treatment, the whole eligible population with access to treatment, the TAS focus of six- and seven-year-olds, and finally in >20-year-olds. We show that the surveillance group under observation has a significant impact on perceived dynamics. Exclusion to treatment and surveillance negatively impacts the probability of reaching public health goals, though in populations that do reach these goals there are no signals to indicate excluded groups. Increasingly restricted surveillance groups over-estimate the efficacy of MDA. The presence of non-treated groups cannot be inferred when surveillance is only occurring in the group receiving treatment.
Bertozzi-Villa A, Bever CAA, Gerardin J, et al., 2023, An archetypes approach to malaria intervention impact mapping: a new framework and example application, MALARIA JOURNAL, Vol: 22
Anderson RM, Cano J, Hollinsworth TD, et al., 2023, Responding to the cuts in UK AID to neglected tropical diseases control programmes in Africa, TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, Vol: 117, Pages: 237-239, ISSN: 0035-9203
Crellen T, Haswell M, Sithithaworn P, et al., 2023, Diagnosis of helminths depends on worm fecundity and the distribution of parasites within hosts, PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 290, ISSN: 0962-8452
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- Citations: 4
Dangerfield CE, David Abrahams I, Budd C, et al., 2023, Getting the most out of maths: How to coordinate mathematical modelling research to support a pandemic, lessons learnt from three initiatives that were part of the COVID-19 response in the UK., J Theor Biol, Vol: 557
In March 2020 mathematics became a key part of the scientific advice to the UK government on the pandemic response to COVID-19. Mathematical and statistical modelling provided critical information on the spread of the virus and the potential impact of different interventions. The unprecedented scale of the challenge led the epidemiological modelling community in the UK to be pushed to its limits. At the same time, mathematical modellers across the country were keen to use their knowledge and skills to support the COVID-19 modelling effort. However, this sudden great interest in epidemiological modelling needed to be coordinated to provide much-needed support, and to limit the burden on epidemiological modellers already very stretched for time. In this paper we describe three initiatives set up in the UK in spring 2020 to coordinate the mathematical sciences research community in supporting mathematical modelling of COVID-19. Each initiative had different primary aims and worked to maximise synergies between the various projects. We reflect on the lessons learnt, highlighting the key roles of pre-existing research collaborations and focal centres of coordination in contributing to the success of these initiatives. We conclude with recommendations about important ways in which the scientific research community could be better prepared for future pandemics. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".
Quaife M, Medley GF, Jit M, et al., 2022, Considering equity in priority setting using transmission models: Recommendations and data needs, Epidemics: the journal of infectious disease dynamics, Vol: 41, Pages: 1-8, ISSN: 1755-4365
ObjectivesDisease transmission models are used in impact assessment and economic evaluations of infectious disease prevention and treatment strategies, prominently so in the COVID-19 response. These models rarely consider dimensions of equity relating to the differential health burden between individuals and groups. We describe concepts and approaches which are useful when considering equity in the priority setting process, and outline the technical choices concerning model structure, outputs, and data requirements needed to use transmission models in analyses of health equity.MethodsWe reviewed the literature on equity concepts and approaches to their application in economic evaluation and undertook a technical consultation on how equity can be incorporated in priority setting for infectious disease control. The technical consultation brought together health economists with an interest in equity-informative economic evaluation, ethicists specialising in public health, mathematical modellers from various disease backgrounds, and representatives of global health funding and technical assistance organisations, to formulate key areas of consensus and recommendations.ResultsWe provide a series of recommendations for applying the Reference Case for Economic Evaluation in Global Health to infectious disease interventions, comprising guidance on 1) the specification of equity concepts; 2) choice of evaluation framework; 3) model structure; and 4) data needs. We present available conceptual and analytical choices, for example how correlation between different equity- and disease-relevant strata should be considered dependent on available data, and outline how assumptions and data limitations can be reported transparently by noting key factors for consideration.ConclusionsCurrent developments in economic evaluations in global health provide a wide range of methodologies to incorporate equity into economic evaluations. Those employing infectious disease models need to use the
Stolk WA, Coffeng LE, Bolay FK, et al., 2022, Comparing antigenaemia- and microfilaraemia as criteria for stopping decisions in lymphatic filariasis elimination programmes in Africa, PLOS NEGLECTED TROPICAL DISEASES, Vol: 16, ISSN: 1935-2735
Borlase A, Le Rutte EA, Castano S, et al., 2022, Evaluating and mitigating the potential indirect effect of COVID-19 on control programmes for seven neglected tropical diseases: a modelling study, LANCET GLOBAL HEALTH, Vol: 10, Pages: E1600-E1611, ISSN: 2214-109X
Davis EL, Hollingsworth TD, 2022, Estimating LFT and qPCR test-sensitivity over time since infection from a human challenge study
<jats:title>Abstract</jats:title><jats:p>Testing has been central to global policy throughout the SARS-CoV-2 pandemic. Understanding how test sensitivity changes after exposure is crucial for the interpretation of test outcomes and the design of testing-based interventions. Using data from a human challenge study, we derive temporal test sensitivity profiles for lateral flow tests (LFT), quantitative polymerase chain reaction (qPCR) tests and viable virus, measured by focus-forming assay (FFA). The median time to detectability was 2 days (throat swab) and 3 days (nasal) for qPCR and 4 days for LFT (both swabs), and there was strong positive correlation between first LFT positive and first FFA positive for both throat (p=0.00019) and nasal (p=0.00032) swabs, supporting the use of LFTs as a method of detecting infectiousness. Peak LFT sensitivity was 82.4% (67.0%-91.8%) for throat samples, occurring 6 days post-exposure and 93.3% (85.1%-98.0%) for nasal, 7 days post-exposure. These temporal profiles provide quantification of the mean behaviour of these tests and individual-based variability and could inform a framework for investigating future testing-based interventions.</jats:p>
Pan D, Sze S, Nazareth J, et al., 2022, The monkeypox case definition in the UK is broad Reply, LANCET, Vol: 400, Pages: 1301-1302, ISSN: 0140-6736
Vegvari C, Abbott S, Ball F, et al., 2022, Commentary on the use of the reproduction number <i>R</i> during the COVID-19 pandemic, STATISTICAL METHODS IN MEDICAL RESEARCH, Vol: 31, Pages: 1675-1685, ISSN: 0962-2802
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- Citations: 7
Mollison D, Isham V, Dangerfield C, et al., 2022, Preface: Challenges for future pandemics, EPIDEMICS, Vol: 40, ISSN: 1755-4365
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- Citations: 1
Bertozzi-Villa A, Bever C, Gerardin J, et al., 2022, An archetypes approach to malaria intervention impact mapping: a new framework and example application
<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>As both mechanistic and geospatial malaria modeling methods become more integrated into malaria policy decisions, there is increasing demand for strategies that combine these two methods. This paper introduces a novel archetypes-based methodology for generating high-resolution intervention impact maps based on mechanistic model simulations. An example configuration of the framework is described and explored.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>First, dimensionality reduction and clustering techniques were applied to rasterized geospatial environmental and mosquito covariates to find archetypal malaria transmission patterns. Next, mechanistic models were run on a representative site from each archetype to assess intervention impact. Finally, these mechanistic results were reprojected onto each pixel to generate full maps of intervention impact. The example configuration used ERA5 and Malaria Atlas Project covariates, singular value decomposition, k-means clustering, and the Institute for Disease Modeling’s EMOD model to explore a range of three-year malaria interventions primarily focused on vector control and case management.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Rainfall, temperature, and mosquito abundance layers were clustered into ten transmission archetypes with distinct properties. Example intervention impact curves and maps highlighted archetype-specific variation in efficacy of vector control interventions. A sensitivity analysis showed that the procedure for selecting representative sites to simulate worked well in all but one archetype.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>This paper introduces a novel methodology which combine
Pan D, Sze S, Nazareth J, et al., 2022, Monkeypox in the UK: arguments for a broader case definition, LANCET, Vol: 399, Pages: 2345-2346, ISSN: 0140-6736
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- Citations: 15
Kumar V, Siddiqui NA, Pollington TM, et al., 2022, Impact of intensified control on visceral leishmaniasis in a highly-endemic district of Bihar, India: an interrupted time series analysis, EPIDEMICS, Vol: 39, ISSN: 1755-4365
Touloupou P, Retkute R, Hollingsworth TD, et al., 2022, Statistical methods for linking geostatistical maps and transmission models: Application to lymphatic filariasis in East Africa, SPATIAL AND SPATIO-TEMPORAL EPIDEMIOLOGY, Vol: 41, ISSN: 1877-5845
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- Citations: 3
Kura K, Ayabina D, Hollingsworth TD, et al., 2022, Determining the optimal strategies to achieve elimination of transmission for <i>Schistosoma mansoni</i>, PARASITES & VECTORS, Vol: 15, ISSN: 1756-3305
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- Citations: 4
Metcalf CJE, Andriamandimby SF, Baker RE, et al., 2021, Challenges in evaluating risks and policy options around endemic establishment or elimination of novel pathogens, EPIDEMICS, Vol: 37, ISSN: 1755-4365
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- Citations: 2
Retkute R, Touloupou P, Basanez M-G, et al., 2021, Integrating geostatistical maps and infectious disease transmission models using Adaptive Multiple Importance Sampling, Annals of Applied Statistics, Vol: 15, Pages: 1980-1998, ISSN: 1932-6157
The Adaptive Multiple Importance Sampling algorithm (AMIS)is an iterative technique which recycles samples from all previousiterations in order to improve the efficiency of the proposal distribution. We have formulated a new statistical framework, based onAMIS, to take the output from a geostatistical model of infectiousdisease prevalence, incidence or relative risk, and project it forwardin time under a mathematical model for transmission dynamics. Weadapted the AMIS algorithm so that it can sample from multiple targets simultaneously by changing the focus of the adaptation at eachiteration. By comparing our approach against the standard AMIS algorithm, we showed that these novel adaptations greatly improve theefficiency of the sampling. We tested the performance of our algorithmon four case studies: ascariasis in Ethiopia, onchocerciasis in Togo,human immunodeficiency virus (HIV) in Botswana, and malaria inthe Democratic Republic of the Congo.
Pan D, Sze S, Martin CA, et al., 2021, Covid-19 and ethnicity: we must seek to understand the drivers of higher transmission, BMJ-BRITISH MEDICAL JOURNAL, Vol: 375, ISSN: 0959-535X
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- Citations: 6
Ayabina DV, Clark J, Bayley H, et al., 2021, Gender-related differences in prevalence, intensity and associated risk factors of <i>Schistosoma</i> infections in Africa: A systematic review and meta-analysis, PLOS NEGLECTED TROPICAL DISEASES, Vol: 15, ISSN: 1935-2735
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- Citations: 11
Anderson RM, Vegvari C, Hollingsworth TD, et al., 2021, The SARS-CoV-2 pandemic: remaining uncertainties in our understanding of the epidemiology and transmission dynamics of the virus, and challenges to be overcome, INTERFACE FOCUS, Vol: 11, ISSN: 2042-8898
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- Citations: 18
Davis EL, Lucas TCD, Borlase A, et al., 2021, Contact tracing is an imperfect tool for controlling COVID-19 transmission and relies on population adherence, NATURE COMMUNICATIONS, Vol: 12
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- Citations: 21
Spencer SEF, Laeyendecker O, Dyson L, et al., 2021, Estimating HIV, HCV and HSV2 incidence from emergency department serosurvey, Gates Open Research, Vol: 5, Pages: 116-116
<ns4:p><ns4:bold>Background: </ns4:bold>Our understanding of pathogens and disease transmission has improved dramatically over the past 100 years, but coinfection, how different pathogens interact with each other, remains a challenge. Cross-sectional serological studies including multiple pathogens offer a crucial insight into this problem. </ns4:p><ns4:p> <ns4:bold>Methods: </ns4:bold>We use data from three cross-sectional serological surveys (in 2003, 2007 and 2013) in a Baltimore emergency department to predict the prevalence for HIV, hepatitis C virus (HCV) and herpes simplex virus, type 2 (HSV2), in a fourth survey (in 2016). We develop a mathematical model to make this prediction and to estimate the incidence of infection and coinfection in each age and ethnic group in each year.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold>Overall we find a much stronger age cohort effect than a time effect, so that, while incidence at a given age may decrease over time, individuals born at similar times experience a more constant force of infection over time.</ns4:p><ns4:p> <ns4:bold>Conclusions: </ns4:bold>These results emphasise the importance of age-cohort counselling and early intervention while people are young. Our approach adds value to data such as these by providing age- and time-specific incidence estimates which could not be obtained any other way, and allows forecasting to enable future public health planning.</ns4:p>
Clark J, Stolk WA, Basáñez M-G, et al., 2021, How modelling can help steer the course set by the World Health Organization 2021-2030 roadmap on neglected tropical diseases, Gates Open Research, Vol: 5, Pages: 112-112
<ns3:p>The World Health Organization recently launched its 2021-2030 roadmap, <ns3:italic>Ending</ns3:italic><ns3:italic> the </ns3:italic><ns3:italic>Neglect</ns3:italic><ns3:italic> to </ns3:italic><ns3:italic>Attain</ns3:italic><ns3:italic> the </ns3:italic><ns3:italic>Sustainable Development Goals</ns3:italic><ns3:italic>,</ns3:italic> an updated call to arms to end the suffering caused by neglected tropical diseases. Modelling and quantitative analyses played a significant role in forming these latest goals. In this collection, we discuss the insights, the resulting recommendations and identified challenges of public health modelling for 13 of the target diseases: Chagas disease, dengue, <ns3:italic>gambiense</ns3:italic> human African trypanosomiasis (gHAT), lymphatic filariasis (LF), onchocerciasis, rabies, scabies, schistosomiasis, soil-transmitted helminthiases (STH), <ns3:italic>Taenia solium</ns3:italic> taeniasis/ cysticercosis, trachoma, visceral leishmaniasis (VL) and yaws. This piece reflects the three cross-cutting themes identified across the collection, regarding the contribution that modelling can make to timelines, programme design, drug development and clinical trials.</ns3:p>
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