The distribution of long-lasting, insecticide-treated nets (ITNs) is a recognized tool for reducing the transmission of malaria in malaria-endemic countries. Initial distributions focused on vulnerable pregnant women and children under 5 years old to reduce mortality, using distribution through antenatal and vaccination clinics [1–5], social marketing [6–8] and targeted mass campaigns [9–18]. Since WHO’s call for universal ITN coverage [19], over 1 billion ITNs have been distributed through mass campaigns [20], generally implemented every 3 years, which replaces all existing ITNs as accounting for existing ITNs in households is not operationally practical [21]. A recent study found that 68% of the 40% reduction in malaria incidence between 2010 and 2015 could be attributed to ITNs [22].

Malaria is endemic in 90% of Madagascar, while the entire country is considered to be at risk for malaria [23]. Prior to 2010, the Madagascar Ministry of Health, supported by international partners and donors, focused ITN distribution strategies on key at-risk populations, specifically pregnant women and children under 5 years old, through antenatal care (ANC) and immunization clinics. Highly subsidized nets were also available through social marketing channels [23]. The 2007 mass campaign, integrated with measles vaccination, mebendazole and vitamin A, distributed more than 1.5 million ITNs to children and pregnant women, resulting in 77% household ownership of at least 1 ITN [9]. The 2009–2010 mass campaign aimed at delivering 2 ITNs per household [24]. Post 2010, the Madagascar National Strategic Plan for Malaria shifted from targeted distribution to mass distribution, with a goal of universal coverage with 1 ITN per 2 persons [23]. In late 2012, through a mass distribution campaign implemented by the National Malaria Control Programme (NMCP) and partners, 5,614,456 nets were distributed in 61 districts in order to achieve universal ITN coverage [25]. However, it is clear that ITN ownership and access decline between campaigns due to net loss, wear and tear, population movements, and births of new family members, reducing ITN coverage to levels as low as 40% before the next campaign [26]. In order to maintain universal coverage more consistently, other mechanisms of ITN distribution are needed [27].

WHO recommends that countries that have strengthened routine ITN distribution through health facilities explore ways to move away from mass campaigns and maintain universal coverage through a combination of health facility distribution and continuous distribution (CD) through schools and/or community-based channels [28]. However, evidence showing that these combinations can maintain high levels of ITN ownership and access in between, or in the absence of, mass campaigns is limited. Therefore, a community-based distribution system was piloted in Tomasina II District on the east coast of Madagascar in 2013–2014. This scheme was conceived as a way to provide families with the opportunity to obtain new nets when they need them, through existing community channels. The goal of the pilot was to maintain household ownership of at least 1 ITN at or above 90%.

Eighteen months after the last mass campaign, and following the 9-month community-based ITN distribution pilot programme, population ITN access was over the target level of 80%. Nearly 100% of households owned at least 1 ITN, and 61% owned at least 1 ITN for 2 people. While a baseline comparison was not possible, by excluding ITNs obtained from the community distribution from the analysis, it can be estimated that had the pilot not occurred, only 55.4% of the population would have had access to an ITN, and only 18.8% of households would have owned 1 ITN for every 2 people, far below universal coverage targets. Two-thirds of households reported requesting a coupon because they did not have enough ITNs or because their ITNs had worn out or been lost; this suggests coverage had indeed declined since the campaign.

These results demonstrate that a combination of mass distribution campaigns and ongoing continuous distribution can achieve current targets for population ITN access. Achieving targets on universal access remains illusory for most countries. The results of this pilot demonstrate it is achievable with a combination of different distribution approaches. It is likely that no single distribution channel will achieve coverage and access targets in the large majority of settings.

However, if continuous systems can successfully sustain high levels of ITN access up until the next scheduled campaign, the campaign could be potentially replacing a higher proportion of relatively new ITNs. This may be considered oversupply or over-allocation. As Bhatt et al. showed, due to repeated mass campaigns, 22–32% of ITNs were estimated to be over-allocated in 2013 [31], and this rate is likely to increase if robust continuous channels are added to repeated mass campaigns. In contrast, data on robust, longer-term continuous distribution approaches are very limited; it is as yet unknown whether these approaches can achieve and sustain coverage and access over the longer term. Furthermore, the cost of determining who really requires a replacement net and who does not may ultimately cost more than the costs involved in over-supplying some ITNs to a community. Finding the best combinations of channels to distribute enough ITNs to reach coverage targets, but not too many, is one of many challenges faced by the global malaria community.

The percentage of households that contacted a community agent was higher among the two poorest quintiles and lowest among the richest quintile, suggesting community-based distribution can succeed in reaching those in greatest need. This is in contrast to findings from South Sudan, where a similar community ITN distribution programme was pro-rich, because poorer households were less likely to have heard about it [32]. It should be noted, however, that both settings are comprised of generally quite poor populations.

Community acceptability of the scheme was good, with close to 90% of beneficiaries reporting that the system was fair, the distances to obtain coupons and nets were short, the community agents were accessible, and the eligibility criteria were acceptable or good. Among the 94 households that requested a coupon but did not get one, only 15% said this was because the agent did not have any coupons; the remainder reported they either did not know why they did not get one, or because they did not meet the criteria, indicating that additional SBCC may be helpful in clarify the eligibility criteria to the beneficiary as well as to the community agents. The very low number of nets reported to have been obtained without a coupon (8) is also striking. The detailed tracking system used by ODDIT and CRS to document the flow of nets to individual religious leaders likely also contributed to a heightened sense of accountability. It suggests that the design of this community mechanism was able to draw strength from a social norm that this system should not be abused.

SBCC activities contributed significantly to the effectiveness of the programme. Families that received information about the scheme were more likely to have contacted a community agent to obtain a new net, and more likely have all family members sleeping under an ITN the night before. SBCC is an important component to any targeted distribution scheme and especially for a new program that requires the beneficiary to engage at multiple levels in the process. Programme planners should design SBCC activities that ensure community awareness of the scheme, provide clear information about eligibility criteria, and describe the steps of the process to request coupons and obtain ITNs, in addition to generalized messaging promoting ITN use.

The finding that ITN use was lower among children under 5 than among the general population is contrary to findings from other studies in Madagascar, where children under 5 are prioritized for ITN use [9, 33, 34]. In the 2016, 2013 and 2011 Malaria Indicator Surveys, under-5 ITN use was consistently 5–8% points higher than overall population ITN use [35–37], indicating that these results may be an anomaly.

Community-based distribution is challenging to implement, requiring training, ongoing supervision and strong logistics and supply chains not only for the ITNs but for the coupons and record-keeping supplies. Strong community networks are a prerequisite for community-based distribution; Madagascar has a history of community initiatives, and with the significant support provided through local NGOs [23, 38–42], but a pilot in a single district is quite different than regional or national scale-up. Costs of this pilot were not evaluated, but are crucial to consider, as previous research has hypothesized that at scale, community-based distribution may have higher costs per net delivered, due to smaller and more frequent deliveries to village level, and increased training, monitoring and supervision costs, compared to other channels [26]. In part due to the successful implementation of this pilot, Madagascar has included community distribution in its National Malaria Strategy, and is currently implementing community distribution in 6 districts [23]. In combination with free mass distribution campaigns, the community distribution is intended to replace damaged ITNs and to cover new sleeping spaces. It is essential to evaluate this programme at scale and over a longer period of implementation, to better understand how well the channel maintains ITN ownership and access in combination with mass campaigns, or indeed if no mass campaigns are implemented. Likewise, cost analyses and cost-effectiveness of larger-scale community distribution are needed to understand how this approach compares to implementation of repeated mass campaigns, and other combinations of distribution channels.

While this pilot was not designed to test whether community-based distribution could replace mass distribution, the evaluation of the pilot did show that community distribution can provide enough ITNs to sustain coverage 18 months after the last mass campaign. Indeed, the results indicate that the combination of a mass campaign with community distribution achieves sustained high coverage. The study also suggests that a community-based system has the potential to make ITNs available to the community without interruption. In principle, household demand for ITNs will reflect their needs, and a community-distribution scheme can supply ITNs when and where they are needed, potentially reducing oversupply if implemented as the primary ITN channel. However, without checks and balances, households may have opportunities to continuously request new free ITNs even if they are not needed, or may, in this system, be incentivized to not take care of their ITNs because new ones are continuously available. More research is needed to evaluate household ITN use and replacement behaviours in this type of on-demand system.

The largest limitation of this research is the short duration of the pilot implementation. A 9-month pilot is insufficient to fully test whether continuous systems can sustain ITN ownership and access over the long term; implementation periods of 3 or more years would provide more comprehensive answers to the research questions. A second limitation is that no baseline was conducted, due to inadequate funding and time constraints. The analysis excluding the community ITNs is an estimation; it must be acknowledged that households may have been more motivated to obtain additional ITNs through other channels, including markets or other commercial channels, had the community ITNs not been available. On the other hand, other studies have shown that 18 months after mass campaigns, ITN indicators fall as nets wear out and are discarded [28, 43–47]. We would not expect ITN ownership and population ITN access to remain above Roll Back Malaria target levels a year and a half after the mass campaign, as they did here.

Household ITN ownership and population ITN access exceeded Roll Back Malaria target levels 18 months following a mass campaign and after a 9-month community distribution pilot in Toamasina II District in Madagascar. The pilot successfully provided coupons and ITNs to households requesting them, particularly for the least poor wealth quintiles, and the scheme was well perceived by communities. Further research is needed to determine whether community-based distribution can sustain ITN ownership and access over the long term, how continuous availability of ITNs affects household net replacement behaviour, and whether community-based distribution is cost-effective in combination with mass campaigns and/or other continuous channels.