Malaria Prevention: Is Combining Bed Nets and Spraying Worth the Cost?
"A new study from Ethiopia weighs the cost-effectiveness of different malaria prevention strategies, revealing surprising insights for public health officials."
Malaria remains a significant public health challenge in many parts of the world, demanding effective and affordable prevention strategies. Two widely used interventions are long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), both proven to reduce malaria transmission. However, the question of whether combining these methods offers a cost-effective advantage over using them separately has been a subject of ongoing debate.
A recent study conducted in Ethiopia delved into this very question, comparing the cost-effectiveness of combined LLIN and IRS implementation against LLINs alone, IRS alone, and routine practices. The findings offer valuable insights for public health officials and policymakers grappling with resource allocation decisions in malaria prevention.
This article breaks down the study's methodology, results, and conclusions, providing a clear understanding of the economic implications of different malaria prevention strategies. We will explore the factors that influence cost-effectiveness and highlight the key takeaways for optimizing malaria control efforts.
Malaria’s Economic Burden and Evidence Gaps
A 2022 systematic review describes malaria as carrying a very large disease burden, while noting that comprehensive, comparable cost estimates across endemic countries are scarce. That lack of comparable cost data complicates policymakers’ efforts to set priorities, allocate resources, and evaluate prevention and control strategies. A 2021 review updated earlier estimates of malaria-control intervention costs and cost-effectiveness, adding evidence intended to inform national malaria-control decisions. A 2026 review also assessed economic evaluations of malaria prevention and treatment, extracting intervention types, comparators, outcomes, costs, and incremental cost-effectiveness ratios.
Economic Evaluation and Its Challenges
Economic evaluation of malaria control interventions uses methodological approaches to quantify the costs and benefits of strategies intended to reduce the disease burden. Common forms include cost-effectiveness, cost-utility, and cost-benefit analyses. However, malaria decision problems can challenge the application of standard health-economic methods; one identified challenge is evaluating cost-effectiveness as incidence declines during an elimination campaign. These methods therefore need to account for features of malaria-control decisions rather than assume that general evaluation approaches transfer without difficulty.
The Cost-Effectiveness Conundrum: LLINs, IRS, or Both?
The Ethiopian study employed a rigorous approach to assess the cost-effectiveness of different malaria prevention strategies. Researchers conducted a cluster randomized controlled trial in the Adami Tullu district, following households over a period from 2014 to 2016. Alongside this trial, they performed a literature-based cost-effectiveness analysis, drawing on effectiveness data from a systematic review of published articles.
- Routine Practice: Relied on existing malaria control activities, with a baseline LLIN coverage of 11%.
- LLINs Alone: Universal coverage with long-lasting insecticidal nets, ensuring every household received nets based on family size.
- IRS Alone: Universal coverage with indoor residual spraying using Propoxur, conducted annually.
- Combined Intervention (LLINs + IRS): Integrated both LLIN distribution and indoor residual spraying.
Recent Evidence on Cost-Effectiveness
A 2026 systematic review concluded that most malaria interventions assessed in Sub-Saharan Africa were highly cost-effective, including long-lasting insecticidal nets (LLINs), PBO nets, indoor residual spraying (IRS) with Actellic or 3GIRS, and combined LLIN plus IRS. The review also listed seasonal and perennial malaria chemoprevention (SMC/PDMC), intermittent preventive treatment in pregnancy (IPTp), and artemisinin-based combination therapy with rapid diagnostic testing (ACT + RDT) among the interventions it found highly cost-effective. Separately, a 2025 cross-sectional study in Southwest Ethiopia reported an association between household heads’ higher education and better insecticide-treated bed-net practices (AOR = 0.28, 95% CI 0.12–0.63, p ≤ 0.01). A systematic review of Ethiopian economic evaluations reported that 11 studies with QHES scores of at least 75% were cost-utility analyses, while a 2024 analysis noted a paucity of published cost-effectiveness studies with QALY or DALY health outcomes.
Combined Prevention May Not Always Be Cost-Effective
An Ethiopia analysis comparing LLINs and IRS alone with their combined use found that, at a willingness-to-pay threshold of one times GDP per capita, only LLINs alone were likely to be cost-effective. In that analysis, IRS was dominated by LLINs, meaning it was more costly and less effective. The finding cautions against assuming that adding spraying to bed nets will provide good value in every setting; the result is specific to the study’s Ethiopian comparison and stated threshold.
Key Takeaways: Making Informed Decisions
The Ethiopian study provides critical insights for malaria prevention efforts. While the trial-based analysis suggested that routine practices were more cost-effective due to lower costs and similar health outcomes, the literature-based analysis painted a different picture. This analysis indicated that LLINs alone are likely cost-effective compared to a willingness-to-pay threshold of three times Ethiopia's GDP per DALY averted.
Cost-Effectiveness Depends on Context
A 2005 generalized cost-effectiveness analysis assessed selected malaria-control interventions in the context of reaching the Millennium Development Goals for malaria. Its efficacy inputs came from the literature and the authors’ calculations, supported by expert opinion, while costs and cost-effectiveness were also the subject of a later 2021 systematic literature review. Together, these sources frame economic evaluation as evidence assembled from intervention outcomes, costs, and assumptions; they do not establish that one prevention combination is the best choice in every setting.
Planning for Sustainable Prevention
A 2025 discussion of malaria-prevention policy calls for robust cost data, clear cost-effectiveness analyses, and careful planning to integrate innovations with existing interventions. It links this planning need to both immediate reductions in malaria burden and longer-term elimination goals, with sustainability as a consideration. A 2026 review describes future prevention as a comprehensive, multilayered strategy combining established and novel interventions. It identifies the WHO-recommended rollout of RTS,S/AS01 and R21/Matrix-M vaccines as a major advance that must be integrated effectively with existing control measures.
Coverage, Equity, and Community Engagement
A 2011 systematic review states that decisions about scaling up malaria interventions should be based on evidence about programme effectiveness, equity, and cost-effectiveness. A 2025 overview of successful malaria-prevention campaigns highlights community engagement, effective communication, access to preventive tools, and ongoing monitoring and evaluation. It describes campaigns using insecticide-treated bed-net distribution and indoor residual spraying as examples of approaches to reducing malaria transmission. These sources emphasize that real-world impact depends on both evidence-informed scale-up and how prevention is delivered to communities.
The cost-effectiveness of the combined intervention (LLINs + IRS) hinges on several factors, particularly the annual malaria probability in the area and the protective-effectiveness of the combined approach. The study revealed that the annual malaria incidence needs to be at least 13% and the protective-effectiveness of combined implementation should be at least 53% for the combined intervention to be considered cost-effective.
Ultimately, the decision of which malaria prevention strategy to implement requires careful consideration of local context, including malaria transmission rates, intervention costs, and the desired level of protection. By understanding these factors, public health officials can make informed decisions to optimize resource allocation and maximize the impact of malaria control programs.