Improving helminth treatment access: costs and opportunities

Soil-transmitted helminths affect about 1·5 billion people living in the world's poorest regions.1Karagiannis-Voules DA Biedermann P Ekpo UF et al.Spatial and temporal distribution of soil-transmitted helminth infection in sub-Saharan Africa: a systematic review and geostatistical meta-analysis.Lancet Infect Dis. 2015; 15: 74-84Summary Full Text Full Text PDF PubMed Scopus (121) Google Scholar The main public health strategy for morbidity control is mass drug administration (MDA; also referred to as preventive chemotherapy), which is the widespread empirical treatment of populations, traditionally school-aged children.2WHOHelminth control in school-age children: a guide for managers of control programmes. World Health Organization, Geneva2011Google Scholar WHO set a goal of achieving 75% coverage of at-risk populations by 2020, but estimates from 2014 suggest only 47% global coverage of children.3WHOPreventive chemotherapy for helminth diseases: progress report, 2014.Wkly Epidemiol Rec. 2016; 91: 93-103PubMed Google Scholar To reach the WHO 2020 goal, opportunities must be taken to find cost efficiencies, collaborate across health sectors, and improve measurement of the costs and effects of MDA programmes. The substantial gap in target coverage for treatment of soil-transmitted helminths poses a great challenge, but an even greater opportunity to address the global burden from these infections. In The Lancet Infectious Diseases, Hugo Turner and colleagues4Turner HC Truscott JE Fleming FM Hollingsworth TD Brooker SJ Anderson RM Cost-effectiveness of scaling up mass drug administration for the control of soil-transmitted helminths: a comparison of cost function and constant costs analyses.Lancet Infect Dis. 2016; (published online Feb 17.)http://dx.doi.org/10.1016/S1473-3099(15)00268-6Google Scholar present a much needed and pragmatic analysis to address knowledge gaps in the cost of school-based MDA against soil-transmitted helminths. In their analysis, they used 3 years of programmatic cost data from six Ugandan districts, and found a relation between higher coverage and lower per-treatment delivery cost (known as economies of scale). Their primary finding that economies of scale apply to MDA, although suspected, had yet to be fully assessed for soil-transmitted helminths. The investigators showed the implications of this finding by using a case study to examine the cost-effectiveness of school-based MDA targeting Ascaris lumbricoides. They found that cost-effectiveness increased with greater treatment coverage when economies of scale were considered, by contrast with projections using a constant cost per treatment, irrespective of coverage, in which cost-effectiveness decreased with scale. For example, when control was scaled up 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 when using the cost function, but to decrease when assuming a constant cost per treatment. The investigators suggest that past assumptions of constant costs can therefore be misleading in select cases. The implication of this finding is that past cost-effectiveness estimates were conservative, since no cost advantages were assumed with higher coverage. Indeed, these school-based programmes are likely to be even more cost-effective than previously believed when reaching high MDA coverage. As treatment for soil-transmitted helminths is scaled up across countries, substantial opportunities exist to further maximise cost efficiencies through co-delivery of soil-transmitted helminth treatment programmes with other MDAs and general health programming. Such opportunities for an integrated platform that combines soil-transmitted helminth treatment with other health programmes exist across a range of interventions, including other MDAs for neglected tropical diseases (eg, schistosomiasis, lymphatic filariasis, onchocerciasis, and trachoma);5Molyneux DH Hotez PJ Fenwick A “Rapid-impact interventions”: how a policy of integrated control for Africa's neglected tropical diseases could benefit the poor.PLoS Med. 2005; 2: e336Crossref PubMed Scopus (392) Google Scholar, 6Lo NC Bogoch II Blackburn BG et al.Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.Lancet Glob Health. 2015; 3: e629-e638Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar infectious diseases (eg, HIV, tuberculosis, and malaria);7Hotez PJ Molyneux DH Fenwick A Ottesen E Ehrlich Sachs S Sachs JD Incorporating a rapid-impact package for neglected tropical diseases with programs for HIV/AIDS, tuberculosis, and malaria.PLoS Med. 2006; 3: e102Crossref PubMed Scopus (606) Google Scholar improvements in water, sanitation, and hygiene programming;8Freeman MC Ogden S Jacobson J et al.Integration of water, sanitation, and hygiene for the prevention and control of neglected tropical diseases: a rationale for inter-sectoral collaboration.PLoS Negl Trop Dis. 2013; 7: e2439Crossref PubMed Scopus (136) Google Scholar general public health programmes (eg, vaccination campaigns and vitamin A supplementation campaigns);9Strunz EC Suchdev PS Addiss DG Soil-transmitted helminthiasis and vitamin A deficiency: two problems, one policy.Trends Parasitol. 2016; 32: 10-18Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar and even household surveys (eg, demographic and health surveys via the DHS Program). Integrated programming is likely to result in cost savings, biological synergies in which several health interventions boost each other's effect, and a unique opportunity to break down traditional disease silos and collaborate across sectors to improve health care.5Molyneux DH Hotez PJ Fenwick A “Rapid-impact interventions”: how a policy of integrated control for Africa's neglected tropical diseases could benefit the poor.PLoS Med. 2005; 2: e336Crossref PubMed Scopus (392) Google Scholar, 6Lo NC Bogoch II Blackburn BG et al.Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.Lancet Glob Health. 2015; 3: e629-e638Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 7Hotez PJ Molyneux DH Fenwick A Ottesen E Ehrlich Sachs S Sachs JD Incorporating a rapid-impact package for neglected tropical diseases with programs for HIV/AIDS, tuberculosis, and malaria.PLoS Med. 2006; 3: e102Crossref PubMed Scopus (606) Google Scholar, 9Strunz EC Suchdev PS Addiss DG Soil-transmitted helminthiasis and vitamin A deficiency: two problems, one policy.Trends Parasitol. 2016; 32: 10-18Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 10Ezeamama AE McGarvey ST Acosta LP et al.The synergistic effect of concomitant schistosomiasis, hookworm, and trichuris infections on children's anemia burden.PLoS Negl Trop Dis. 2008; 2: e245Crossref PubMed Scopus (88) Google Scholar For cost-effectiveness studies, further investigation is needed to improve understanding of disability from helminth infections and formalise a consensus on more conventional outcome measures, including the disability-adjusted life-year.11WHOWHO guide to cost-effectiveness analysis.http://www.who.int/choice/publications/p_2003_generalised_cea.pdfDate: 2003Google Scholar This metric enables economic comparisons across many different health interventions to inform health-care spending,11WHOWHO guide to cost-effectiveness analysis.http://www.who.int/choice/publications/p_2003_generalised_cea.pdfDate: 2003Google Scholar and can include all health benefits accrued with individual treatment (eg, albendazole treats many helminths, including A lumbricoides, hookworm, and Trichuris trichiura). Turner and colleagues4Turner HC Truscott JE Fleming FM Hollingsworth TD Brooker SJ Anderson RM Cost-effectiveness of scaling up mass drug administration for the control of soil-transmitted helminths: a comparison of cost function and constant costs analyses.Lancet Infect Dis. 2016; (published online Feb 17.)http://dx.doi.org/10.1016/S1473-3099(15)00268-6Google Scholar reported effectiveness outcomes of worm-years averted, prevalent infection case-years averted, and heavy infection case-years averted. The challenge with some of these outcome measures is the important non-linear relations between prevalence, worm burden (ie, infection intensity), and disability, and also limited knowledge about the effect of minor differences in number of worms on an individual's disability. The investigators presumably chose these outcomes—as opposed to disability-adjusted life-years—because of controversy regarding use of a disability weight that adequately captures all disease morbidity. Nevertheless, to accurately make economic comparisons among MDA and other competing health priorities, collaborative development of a consensus regarding disability weights and collection of additional data if there is substantial uncertainty will be important. The investigators also highlight remaining data limitations that can guide future research on programmatic treatment of helminths. Although their analysis focused on school-based programming, evidence and global support is increasing for expansion of treatment from only school-aged children to entire communities to approach disease elimination and avert the substantial morbidity in both children and adults, even if elimination is not reached.6Lo NC Bogoch II Blackburn BG et al.Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.Lancet Glob Health. 2015; 3: e629-e638Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 12Anderson R Truscott J Hollingsworth TD The coverage and frequency of mass drug administration required to eliminate persistent transmission of soil-transmitted helminths.Philos Trans R Soc Lond B Biol Sci. 2014; 369: 20130435Crossref PubMed Scopus (127) Google Scholar As the investigators discuss, future studies should examine the relation between coverage and cost of community-wide treatment and the increased cost of reaching repeatedly untreated populations (ie, hard-to-reach populations). Furthermore, the study findings of a lower per-person treatment cost associated with higher coverage suggests that populations are likely to be able to receive treatment at a lower prevalence than recommended currently.2WHOHelminth control in school-age children: a guide for managers of control programmes. World Health Organization, Geneva2011Google Scholar This finding suggests the importance of re-examining current MDA guidelines for helminth infections, and potentially lowering the prevalence thresholds for MDA in these settings.6Lo NC Bogoch II Blackburn BG et al.Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.Lancet Glob Health. 2015; 3: e629-e638Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar Since individual countries determine health priorities, treatment of helminth infections—especially when integrated with other health programming—provides an attractive and cost-effective option. To reach the WHO 2020 goal for 75% coverage, there are great opportunities to integrate soil-transmitted helminth treatment with other health programming, use research to guide programmatic treatment delivery, and improve the measurement of the effect of MDA. If we ignore these opportunities, then we will have to consider the cost of failing to do our best to reach the populations who bear the burden of helminth infections. We declare no competing interests. Cost-effectiveness of scaling up mass drug administration for the control of soil-transmitted helminths: a comparison of cost function and constant costs analysesThe 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. Full-Text PDF Open Access

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