The success of elimination programs is directly related to treatment coverage rates in annual mass drug administration (MDA) campaigns. While mathematical models suggest that high annual MDA coverage will lead to a decrease in the number of annual treatment cycles required to achieve success, critical assumptions may not be adequately addressed. For example, these models assume that non-treatment during MDAs is not systematic, i.e. all persons are eventually treated. Realistically, though, there are numerous programmatic situations in which segments of the target populations may fail to have adequate access to MDA or other NTD interventions.
These unique programmatic challenges may include settings in which large populations have migrated (or are internally displaced) as a result of natural disasters or civil strife, urban populations, economic migrants and groups not reached or convinced by social mobilization strategies. The contribution of these groups to ongoing transmission has not been quantitatively addressed, but intuitively, these hard-to-reach groups must represent a threat to the elimination goals when the prevalence of the targeted NTD is high in that subpopulation, and when the group represents a significant proportion of the total population. In addition to challenges with MDA, this priority also aims to address barriers to DMDI program implementation strategies including case finding and identification, integration of patients into the health care system, and integration of NTD DMDI services into universal health care. Defining strategies to address these challenges, either directly by improving social mobilization or indirectly by increasing the performance of community drug distributors, will improve the effectiveness of NTD programs and address fundamental questions of equity.