Review 1: "Cost-effectiveness of End-game Strategies Against Sleeping Sickness across the Democratic Republic of Congo"

RR:C19 Evidence Scale rating by reviewer:

• Strong. The main study claims are very well-justified by the data and analytic methods used. There is little room for doubt that the study produced has very similar results and conclusions as compared with the hypothetical ideal study. The study’s main claims should be considered conclusive and actionable without reservation.

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Review: Antillon et al. aim to answer the following questions: by 2030 or 2040, could the Democratic Republic of Congo achieve elimination of transmission of sleeping sickness through a combination of passive screening, active screening, and vector control (where the mixture and levels of activities could vary across the Country’s health zones)? The authors also ask whether transmission elimination can be epidemiologically achieved, with what programmatic mixture and scale, at which price, and whether the necessary level of investment could be considered cost-saving or cost-effective.

The concepts of disease control (lessening a disease’s burden), elimination (halting or containing to very small geographic areas the transmission of a disease) and eradication (permanently ending the transmission and impact of a disease) are core concepts of public health (as well articulated by The Task Force for Global Health, CDC, and others). However, the concepts of elimination and eradication are underutilized seemingly because often when we approach a stage in which a disease might reach these extremely low levels, societal commitment to addressing that public health challenge tends to wane because the threat is no longer perceived as urgent. Divergent and dynamic are the views about what one should be willing to pay to truly eliminate or eradicate a disease. One potential reason for such divergence of views is that the literature contains very few examples of careful, quantitative analyses of what strategic programmatic actions would need to be taken, where, at what scale, and for how long to achieve elimination or eradication of a disease; without such data and analytic inputs, elimination and eradication debates can be relatively under-informed. 

The paper here under review attempts to fill that analytic void for one particular public health challenge. Antillon et al. deliver an exemplary analysis that aims to answer the following questions: by 2030 or 2040, could the Democratic Republic of Congo achieve elimination of transmission of sleeping sickness through a combination of passive screening, active screening, and vector control (where the mixture and levels of activities could vary across the Country’s health zones)? The authors ask whether transmission elimination can be epidemiologically achieved, with what programmatic mixture and scale, at which price, and whether the necessary level of investment could be considered cost-saving or cost-effective. The authors rightly recognize that the decline of sleeping sickness cases and associated deaths in recent years should be considered a time for concerted action to reach elimination, rather than a time for complacency to hope that remaining cases will somehow dissipate. 

Antillon et al. use a well-developed and previously published modeling strategy (recently updated in important ways, for instance moving from a deterministic to a stochastic model) to answer these questions in a careful manner, all the while transparently describing the limitations of and uncertainty in the model and input parameter values. The analyses estimate that the vast majority of health zones in the Democratic Republic of Congo can achieve sleeping sickness transmission elimination by 2030 (even more by 2040) with either expansion of current activities (listed above) or changing the mixture of the public health services to better meet local needs. This latter point is illustrated by the model’s recommendations for vector control being more tightly focused on health zones in which rivers are present. 

The model’s economic evaluation components find that for many health zones in the country the efforts needed for successful elimination of transmission would be considered cost-saving or cost-effective by well-accepted global public health standards. However, in a small number of health zones, the needed investment might exceed the cost-effective threshold of $500 willingness to pay per disability-adjusted life year saved; still, the estimation of this price tag is critically important for informing policy discussions about making the needed elimination investment at both the health zone and national level (as well as informing funders of global health efforts). 

The work of Antillon et al. is an important example of how to quantitatively inform disease elimination and eradication programmatic and policy discussions.