Preventive chemotherapy coverage for neglected tropical diseases: does one metric fit all?
Authors: Elizabeth A Cromwell, Nancy Fullman
Journal: The Lancet Global Health (2018)

Preventive chemotherapy for neglected tropical diseases (NTDs) is implemented through mass drug administration (MDA) to eligible populations in NTD-endemic areas on the assumption that such treatment will reduce the reservoir of infection and eventually interrupt transmission. Timely tracking of MDA programme performance within broader health systems is important, particularly as countries aim to improve interventions to control and eliminate NTDs. Yet such efforts also must reflect the unique nature of MDA, which can vary between NTDs and locales—a challenge when developing one metric to fit all monitoring needs. MDA typically occurs within communities via a robust network of local volunteers, positioning MDA among the few public health interventions accessible to the world's most vulnerable people. The scale of MDA for NTDs is massive, with about 1 billion people receiving preventive chemotherapy for one or more NTDs in 2015.1WHOCrossing the billion. Lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases and trachoma: preventive chemotherapy for neglected tropical diseases. World Health Organization, Geneva2017Google Scholar Beyond immediate health benefits, preventive chemotherapy by MDA also has positive effects on school attendance, increases economic productivity,2Hotez PJ Fenwick A Savioli L Molyneux DH Rescuing the bottom billion through control of neglected tropical diseases.Lancet. 2009; 373: 1570-1575Summary Full Text Full Text PDF PubMed Scopus (616) Google Scholar improves child health,3Hall A Hewitt G Tuffrey V de Silva N A review and meta-analysis of the impact of intestinal worms on child growth and nutrition.Matern Child Nutr. 2008; 4: 118-236Crossref PubMed Scopus (244) Google Scholar and reduces mortality.4Keenan JD Bailey RL West SK et al.Azithromycin to reduce childhood mortality in sub-Saharan Africa.N Engl J Med. 2018; 378: 1583-1592Crossref PubMed Scopus (190) Google Scholar Furthermore, NTD control and elimination is expressly prioritised within the Sustainable Development Goal (SDGs). When large-scale MDA implementation first began, monitoring occurred through vertical, single-disease programmes. In recent years, calls to integrate MDA and NTD programme measurement within broader health system monitoring have become more emphatic. In The Lancet Global Health, Christopher Fitzpatrick and colleagues5Fitzpatrick C Bangert M Mbabazi PS et al.Monitoring equity in universal health coverage with essential services for neglected tropical diseases: an analysis of data reported for five diseases in 123 countries over 9 years.Lancet Glob Health. 2018; (published online July 24.)http://dx.doi.org/10.1016/S2214-109X(18)30307-3Summary Full Text Full Text PDF PubMed Scopus (17) Google Scholar developed an NTD service coverage index based on preventive chemotherapy for trachoma, lymphatic filariasis, onchocerciasis, soil-transmitted helminths, and schistosomiasis, proposing the first-ever aggregate NTD programme performance metric for MDA. The NTD service coverage index is meant to complement the universal health coverage (UHC) service coverage index,6Hogan DR Stevens GA Hosseinpoor AR Boerma T Monitoring universal health coverage within the Sustainable Development Goals: development and baseline data for an index of essential health services.Lancet Glob Health. 2018; 6: e152-e168Summary Full Text Full Text PDF PubMed Scopus (188) Google Scholar a measure designed to benchmark UHC service coverage progress related to the SDGs. The NTD index equals the geometric mean of national MDA coverage, which is routinely reported for NTDs in endemic countries that can be treated by preventive chemotherapy. Using reported MDA coverage data has its limitations,7Worrell C Mathieu E Drug coverage surveys for neglected tropical diseases: 10 years of field experience.Am J Trop Med Hyg. 2012; 87: 216-222Crossref PubMed Scopus (34) Google Scholar as recognised by the authors, since reporting biases or errors can occur with eligible populations and treatments provided. Ideally, NTD programme progress would be measured by broader interventions received (ie, vector control, hygiene promotion, and water and sanitation improvements) and case management; however, data are not consistently available for all of these key interventions and services. Fitzpatrick and colleagues compared NTD index performance with the UHC service coverage index, eliciting important questions and considerations. For example, several countries (eg, Ghana, Malawi, Sierra Leone, Togo) had higher NTD index scores than UHC service coverage. Do these findings imply weaker UHC services but stronger community networks in these countries? High NTD index scores could be indicative of successful community-based delivery models and thus opportunities to leverage these platforms for new interventions. Furthermore, had countries been solely ranked on their UHC service coverage scores, Togo and Malawi's successful NTD programmes, which have met lymphatic filariasis elimination goals, would be ignored. Conversely, other factors might contribute to observed differences in these two indices. The variability of MDA funding, and implementation (particularly as it relates to external funding and its intersection with primary care8Gyapong JO Gyapong M Yellu N et al.Integration of control of neglected tropical diseases into health-care systems: challenges and opportunities.Lancet. 2010; 375: 160-165Summary Full Text Full Text PDF PubMed Scopus (101) Google Scholar or broader health system functions) might have very different effects in improving preventive chemotherapy coverage versus UHC. How well the UHC service coverage index represents overall performance is another issue; its current formulation9Fullman N Lozano R Towards a meaningful measure of universal health coverage for the next billion.Lancet Glob Health. 2018; 6: e122-e123Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 10WHO Expert Reference Group on the General Programme of Work (WHO ERG GPW13). Preliminary Report, May 2018. World Health Organization, Geneva2018Google Scholar of 14 tracer indicators shows relatively limited health services and levels of care, and large gaps in country–year data representation from 2000–2015 might conflate true differences in coverage with differences in data availability. Although much potential remains for improving measurement, the NTD index, alongside assessments of UHC, offers key entry points for achieving a better understanding of context-specific needs and programme implications to advance intervention delivery across health domains. Fitzpatrick and colleagues also highlight the omission of MDA from the UHC service coverage index, indicating that MDA should be included as part of UHC service packages. In many ways, this view might represent an ideal that, in reality, could be difficult to achieve for most NTD programmes. Most MDA activities rely on external funding and pharmaceutical donations delivered through vertical, community-based platforms that, at minimum, would necessitate massive investments from and restructuring of partnerships with government health entities for successful UHC integration. Furthermore, shifting MDA provision to primary care could possibly lead to reduced preventive chemotherapy coverage, unless health-care access is markedly improved for the world's most vulnerable populations in tandem. That is not to say that preventive chemotherapy initiatives and UHC are inherently incompatible; in fact, NTD programme infrastructures could be leveraged to strengthen networks of primary care and facility-based services. Rather, if or how MDA is included within UHC service packages and delivery platforms requires careful consideration of local contexts and needs, balancing potential long-term benefits of UHC integration with the likely technical, financial, and political challenges in doing so. Ultimately, people in the bottom billion2Hotez PJ Fenwick A Savioli L Molyneux DH Rescuing the bottom billion through control of neglected tropical diseases.Lancet. 2009; 373: 1570-1575Summary Full Text Full Text PDF PubMed Scopus (616) Google Scholar only stand to gain if preventive chemotherapy coverage metrics can be translated into improved NTD control and elimination worldwide. A key step towards this aim is strengthened monitoring of who receives preventive chemotherapy and where the largest gaps remain. We declare no competing interests. Monitoring equity in universal health coverage with essential services for neglected tropical diseases: an analysis of data reported for five diseases in 123 countries over 9 yearsThe NTD index can be used to measure equity in progress towards UHC. A broader NTD index including services for other NTDs could be developed at regional and country levels. Comparing the NTD and UHC service coverage indices reveals that some countries that are performing well by the measure of the UHC service coverage index still have work to do in prioritising services for their poorest and otherwise most marginalised communities. Our results offer hope that socioeconomic barriers to health service coverage can be overcome. Full-Text PDF Open Access