Evaluating the variation in the projected benefit of community-wide mass treatment for schistosomiasis: Implications for future economic evaluations

Background: the majority of schistosomiasis control programmes focus on targeting school-aged children. expanding the use of community-wide mass treatment to reach more adults is under consideration. however,it should be noted that this would require a further increase in programmatic resources,international aid,and commitment for the provision of praziquantel. consequently,it is important to understand (i) where a change of strategy would have the greatest benefit,and (ii) how generalisable the conclusions of field trials and analytical studies based on mathematical models investigating the impact of community-wide mass treatment,are to a broad range of settings. methods: in this paper,we employ a previously described deterministic fully age-structured schistosomiasis transmission model and evaluate the benefit of community-wide mass treatment both in terms of controlling morbidity and eliminating transmission for schistosoma mansoni,across a wide range of epidemiological settings and programmatic scenarios. this included variation in the baseline relative worm pre-control burden in adults,the overall level of transmission in defined settings,choice of effectiveness metric (basing morbidity calculations on prevalence or intensity),the level of school enrolment and treatment compliance. results: community-wide mass treatment was found to be more effective for controlling the transmission of schistosome parasites than using a school-based programme only targeting school-aged children. however,in the context of morbidity control,the potential benefit of switching to community-wide mass treatment was highly variable across the different scenarios analysed. in contrast,for areas where the goal is to eliminate transmission,the projected benefit of community-wide mass treatment was more consistent. conclusion: whether community-wide mass treatment is appropriate will depend on the local epidemiological setting (i.e. the relative pre-control burden in adults and transmission intensity),and whether the goal is morbidity control or eliminating transmission. this has important implications regarding the generalisability of cost-effectiveness analyses of schistosomiasis interventions. our results indicate that areas with poor school-enrolment/coverage could benefit more from community-wide treatment of praziquantel and should potentially be prioritised for any change in strategy. this work highlights the importance of not over-generalising conclusions and policy in this area,but of basing decisions on high quality epidemiological data and quantitative analyses of the impact of interventions in a range of settings. © 2017 the author(s).