Hugo C Turner1, James E Truscott2, Fiona M Fleming3, T Déirdre Hollingsworth4, Simon J Brooker5, Roy M Anderson6. 1. London Centre for Neglected Tropical Disease Research, London, UK; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, London, UK. Electronic address: hugo.turner@imperial.ac.uk. 2. London Centre for Neglected Tropical Disease Research, London, UK; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, London, UK. 3. London Centre for Neglected Tropical Disease Research, London, UK; Schistosomiasis Control Initiative, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, London, UK. 4. Mathematics Institute, University of Warwick, Coventry, UK; School of Life Sciences, University of Warwick, Coventry, UK. 5. Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK. 6. London Centre for Neglected Tropical Disease Research, London, UK.
Abstract
BACKGROUND: The coverage of mass drug administration (MDA) for neglected tropical diseases, such as the soil-transmitted helminths (STHs), needs to rapidly expand to meet WHO's 2020 targets. We aimed to compare use of a cost function to take into account economies of scale to the standard method of assuming a constant cost per treatment when investigating the cost and cost-effectiveness of scaling up a STH MDA programme targeting Ascaris lumbricoides. METHODS: We fitted a cost function describing how the costs of MDA change with scale to empirical cost data and incorporated it into a STH transmission model. Using this cost function, we investigated the consequences of taking into account economies of scale on the projected cost-effectiveness of STH control, by comparison with the standard method of assuming a constant cost per treatment. The cost function was fitted to economic cost data collected as part of a school-based deworming programme in Uganda using maximum likelihood methods. We used the model to investigate the total reduction in the overall worm burden, the total number of prevalent infection case-years averted, and the total number of heavy infection case-years averted. For each year, we calculated the effectiveness as the difference between the worm burden or number of cases and the number in absence of treatment. FINDINGS: When using the cost function, the cost-effectiveness of STH control markedly increased as the programme was scaled up. By contrast, the standard method (constant cost per treatment) undervalued this and generated misleading conclusions. For example, when scaling up control in the projected district from 10% to 75% coverage of at-risk school-age children, the cost-effectiveness in terms of prevention of heavy burden infections was projected to increase by over 70% when using the cost function, but decrease by 18% when assuming a constant cost per treatment. INTERPRETATION: The current exclusion of economies of scale in most economic analyses must be addressed if the most cost-effective policies for the control of neglected tropical diseases are to be formulated. These findings are also relevant to other large-scale disease interventions. FUNDING: GlaxoSmithKline, Bill & Melinda Gates Foundation, Partnership for Child Development, and Wellcome Trust.
BACKGROUND: The coverage of mass drug administration (MDA) for neglected tropical diseases, such as the soil-transmitted helminths (STHs), needs to rapidly expand to meet WHO's 2020 targets. We aimed to compare use of a cost function to take into account economies of scale to the standard method of assuming a constant cost per treatment when investigating the cost and cost-effectiveness of scaling up a STH MDA programme targeting Ascaris lumbricoides. METHODS: We fitted a cost function describing how the costs of MDA change with scale to empirical cost data and incorporated it into a STH transmission model. Using this cost function, we investigated the consequences of taking into account economies of scale on the projected cost-effectiveness of STH control, by comparison with the standard method of assuming a constant cost per treatment. The cost function was fitted to economic cost data collected as part of a school-based deworming programme in Uganda using maximum likelihood methods. We used the model to investigate the total reduction in the overall worm burden, the total number of prevalent infection case-years averted, and the total number of heavy infection case-years averted. For each year, we calculated the effectiveness as the difference between the worm burden or number of cases and the number in absence of treatment. FINDINGS: When using the cost function, the cost-effectiveness of STH control markedly increased as the programme was scaled up. By contrast, the standard method (constant cost per treatment) undervalued this and generated misleading conclusions. For example, when scaling up control in the projected district from 10% to 75% coverage of at-risk school-age children, the cost-effectiveness in terms of prevention of heavy burden infections was projected to increase by over 70% when using the cost function, but decrease by 18% when assuming a constant cost per treatment. INTERPRETATION: The current exclusion of economies of scale in most economic analyses must be addressed if the most cost-effective policies for the control of neglected tropical diseases are to be formulated. These findings are also relevant to other large-scale disease interventions. FUNDING: GlaxoSmithKline, Bill & Melinda Gates Foundation, Partnership for Child Development, and Wellcome Trust.
Authors: Debbie Humphries; Sara Nguyen; Sunny Kumar; Josephine E Quagraine; Joseph Otchere; Lisa M Harrison; Michael Wilson; Michael Cappello Journal: Am J Trop Med Hyg Date: 2016-11-28 Impact factor: 2.345
Authors: Hugo C Turner; James E Truscott; Alison A Bettis; T Déirdre Hollingsworth; Simon J Brooker; Roy M Anderson Journal: Parasite Epidemiol Control Date: 2016-06
Authors: Sarah C L Knowles; Hugh J W Sturrock; Hugo Turner; Jane M Whitton; Charlotte M Gower; Samuel Jemu; Anna E Phillips; Aboulaye Meite; Brent Thomas; Karsor Kollie; Catherine Thomas; Maria P Rebollo; Ben Styles; Michelle Clements; Alan Fenwick; Wendy E Harrison; Fiona M Fleming Journal: PLoS Negl Trop Dis Date: 2017-05-26
Authors: Hugo C Turner; James E Truscott; Alison A Bettis; Sam H Farrell; Arminder K Deol; Jane M Whitton; Fiona M Fleming; Roy M Anderson Journal: Parasit Vectors Date: 2017-04-28 Impact factor: 3.876
Authors: Amy Pinsent; Fengchen Liu; Michael Deiner; Paul Emerson; Ana Bhaktiari; Travis C Porco; Thomas Lietman; Manoj Gambhir Journal: Epidemics Date: 2017-03 Impact factor: 4.396
Authors: Roy Anderson; Sam Farrell; Hugo Turner; Judd Walson; Christl A Donnelly; James Truscott Journal: Parasit Vectors Date: 2017-02-17 Impact factor: 3.876
Authors: Lukyn M Gedge; Alison A Bettis; Mark H Bradley; T Déirdre Hollingsworth; Hugo C Turner Journal: Parasit Vectors Date: 2018-02-01 Impact factor: 4.047
Authors: Sam H Farrell; Luc E Coffeng; James E Truscott; Marleen Werkman; Jaspreet Toor; Sake J de Vlas; Roy M Anderson Journal: Clin Infect Dis Date: 2018-06-01 Impact factor: 9.079