Delivery systems for insecticide treated and untreated mosquito nets in Africa: categorization and outcomes achieved

Coverage of insecticide-treated nets (ITNs) in sub-Saharan Africa is still low despite their proven efficacy, effectiveness and cost-effectiveness. Delivery systems for ITNs have been hotly debated, but there has been no structured approach to assessing their relative effectiveness. This paper aims to: propose a categorization of ITN and mosquito net delivery systems; classify existing systems according to this categorization; critique coverage measures reported; synthesize evidence about the levels of coverage achieved by each system; and identify current analytical gaps and future priorities.

We undertook a systematic review of published papers complemented by grey literature from projects and programmes. A 4-by-3 matrix was developed of delivery sector and cost to end user. Delivery systems were placed in the matrix based on project descriptions. Coverage and equity of coverage outcomes of the identified delivery systems were assessed for consistency with standard Roll Back Malaria (RBM) coverage indicators. These were placed in the matrix for comparison of outcomes by ITN delivery category.

Only 17 references with coverage data were identified, and amongst these there was variation from the RBM indicators. We identified three sets of coverage data where delivery and surveys to assess coverage of target groups were at national scale: public-free delivery in Togo; mixed-partially subsidized delivery in Malawi, and private-unsubsidized delivery in The Gambia. The highest level of household ownership was achieved through public-free delivery (62.5%), whilst use by pregnant women and by children under 5 was highest through private-unsubsidized delivery (67.2 and 67.7%, respectively).

There are no comparative studies of delivery systems for ITNs from which definitive evidence can be drawn, so conclusions on the relative merits of different delivery systems and levels of subsidy cannot be made. Development of methods of attributing household-level outcomes to specific delivery systems would aid in providing this evidence base. As countries scale-up efforts to deliver ITNs, our matrix provides an analytical tool for developing a comprehensive mapping of systems and outcomes. To guide strategic decision-making, cross-country and cross-regional comparisons of the outcomes of systems are needed to facilitate an analysis of the influence of contextual factors.