Malaria kills around 600,000 people annually. Children under five years old in Africa account for about 70% of all malaria deaths worldwide, and around 11% of total malaria deaths are in the Democratic Republic of the Congo (DRC).[1]

As part of our ongoing efforts to scale our research and funding to direct much more money where it can do extraordinary good, GiveWell recently made its largest grant ever: $276 million to fund the purchase and distribution of malaria nets in DRC through the Against Malaria Foundation (AMF).[2] This grant, which we announced earlier this week via our podcast, is being funded by Coefficient Giving and donations to GiveWell’s Top Charities Fund.[3]

We estimate this grant will lead to the distribution of around 92 million insecticide-treated nets (ITNs), 46 million of which we think would not otherwise be distributed, and will avert approximately 67,000 deaths.

The research we conducted as part of this grant investigation led us to two key decisions:

• First, this grant is much larger than our past funding for nets in DRC, enabling the purchase of nets for use across all 26 provinces of DRC from 2027 through 2029 and covering $60 million in distribution costs.[4]
• Second, the funding will shorten the time between regular net distributions to provide additional protection against malaria in up to five provinces with higher malaria burden.

Looking back to move forward

Making such a large grant required an intensive grant investigation process, beginning with an analysis of one of our past grants to AMF for insecticide-treated nets in DRC. In that analysis, we drew on multiple independent data sources, funded qualitative interviews to gather more information, and conducted a novel empirical analysis to deepen our confidence. Those findings fed into our investigation for this grant, where we were able to do more and deeper research than we had in past investigations, increasing our confidence, especially in three areas:

• How effective are insecticide-treated nets at reducing cases of malaria?
• How many children are contracting and dying from malaria in specific areas of DRC?
• How long do the nets provide protection against malaria infections?

These three questions were central to our decision making for this grant, as each informs a key parameter in our cost-effectiveness analysis. GiveWell focuses on identifying the programs that save or improve lives the most per dollar, so that the limited amount of funding available can make the greatest difference. We do that by creating cost-effectiveness analyses of the programs we evaluate.

We used a recent Demographic and Health Survey in DRC as a key data source for our research. These surveys provide important health and mortality data in many low- and middle-income countries by conducting very large in-person, house-to-house surveys that ask women to recall their children’s birth and survival histories. One of these surveys was conducted in DRC in 2023-2024, providing us with a rich resource to inform our grantmaking decision.

We analyzed the survey data, along with a number of other data sources—including hundreds of thousands of household surveys conducted during AMF’s post-distribution monitoring of campaigns that we previously funded.[5] Together, these sources helped increase our confidence in our DRC-specific estimates of the effectiveness of insecticide-treated nets, the duration of net protection, and the overall malaria burden.

That, in turn, led us to make a much larger grant than we had in the past and increase the frequency of net distribution campaigns in areas with particularly high malaria mortality.

Why we made our largest grant ever

Evidence shows that malaria nets, which are typically hung over beds or other sleeping spaces, are effective at protecting people from mosquitoes at night—and significantly reduce the risk of becoming infected with malaria. GiveWell has funded AMF-supported net campaigns in DRC since 2019. Those earlier grants supported nets campaigns in specific areas of DRC, and most of the funding was focused on procuring nets.[6]

This grant does much more. It supports net procurement across all 26 of DRC’s provinces and includes $60 million to cover a portion of the costs to distribute those nets. The process for ordering and procuring nets can take a number of months, and we understand that previous net campaigns in DRC were delayed because the government did not have all the funding to plan a full net cycle up front. By making a large grant that allows planning, ordering, and procuring with a sufficient lead time, we expect to increase the likelihood that the net campaigns occur on schedule.

Three findings from our investigation drove that decision: we confirmed that nets significantly reduce child deaths in DRC, we deepened our confidence that DRC’s malaria burden is exceptionally high, and we found that existing funding couldn’t cover all the areas where campaigns would have a high impact.

Nets significantly reduce child deaths in DRC

We are confident that nets are effective at reducing malaria infections. We estimate that children’s risk of dying from malaria is reduced by 24% to 56% (depending on location) per year of effective protection from a net. This estimate is based on our analysis of Pryce et al. 2018, a systematic review of studies of insecticide-treated nets across a number of countries. While we are confident that nets save lives, we also know that context makes a difference—programs that work in one place often do not have precisely the same effect in another location. As a result, for this grant investigation, we worked to learn more about the effectiveness of nets in DRC specifically.

Net distribution campaigns in DRC take place province by province at different times. As a result, we were able to use the timing of the campaigns relative to the timing of children’s births to measure the length of time that children had protection from nets. We linked each household from a recent Demographic and Health Survey to the most recent insecticide-treated net campaign in its province, calculating the number of months since the campaign mid-point. We then compared mortality in households that were relatively near each other but across province borders, such that households on one side had recently received nets and households on the other side had not.

In the map below you can see the length of time since the most recent nets campaign in each province—one key input into our analysis.

[Note: This blog post is best read on GiveWell’s website, as it includes a number of interactive data visualizations that may not render correctly via email or RSS feed.]

Our analysis found that net campaigns significantly reduced malaria infections and also reduced the overall risk of child death.[7] That finding, along with additional information we gathered about DRC’s malaria burden (described in the section below), provided additional support for the mortality effect estimate we had been using to estimate the cost-effectiveness of this program and increased our confidence that nets work well in the specific locations that would be funded by this grant. To corroborate these results, we contracted with an independent researcher to replicate our analysis; we are currently reviewing results and also intend to submit our work for peer review.

DRC’s malaria burden is among the highest of any location where we’ve funded nets

The areas of DRC we expect to be covered by this grant have among the highest malaria mortality rates in the absence of ITNs for children under five of any geography where we’ve funded net campaigns in recent years: 0.88%, compared to, for example, 0.73% in our recent grant for nets in Nigeria and 0.47% in Côte d’Ivoire. DRC has a relatively high all-cause mortality rate for children and the highest estimated share of deaths due to malaria among these geographies.

However, we were uncertain about that value for DRC, as it is based on a mortality model that relies on limited empirical malaria mortality data. Because of that, over the course of this grant investigation we worked to triangulate additional sources of information to come up with our best estimate of the true value.

We used three sources of data for our calculation of all-cause mortality:

• Institute for Health Metrics and Evaluation’s Global Burden of Disease (GBD) program, a large collaborative research effort that estimates the prevalence, incidence, and mortality of health conditions.
• United Nations Inter-agency Group for Child Mortality Estimation (UN IGME), a collaboration of UNICEF, WHO, the World Bank Group, and the UN Population Division that compiles censuses, surveys, and vital registration data to create mortality estimates.
• 2024 Demographic and Health Surveys survey in DRC, an in-person survey that gathers information from households about health, nutrition, and mortality.

We then used GBD and UN IGME data for our estimates of direct malaria deaths. We think the data is imprecise, so we sought out information from additional sources:

• Health surveys in DRC, including Demographic and Health Surveys and UNICEF’s Multiple Indicator Cluster Surveys (MICS), consistently report high levels of malaria prevalence in DRC.[8]
• DRC has a climate favorable for year-round malaria—nearly the entire population lives in areas with stable malaria transmission for eight to 12 months per year.[9]
• We spoke with a number of DRC-based experts and clinicians, and they consistently cited malaria as a significant driver of mortality in DRC.
• A study that conducted tissue sampling, one strategy for determining cause of death in many low- and middle-income countries, found that malaria was a cause in around 43% of deaths in Sierra Leone (a similar rural context with high malaria transmission), which is broadly similar to our estimate of 56% for DRC.[10]

Together, these sources of information lead us to be confident that malaria is a significant cause of child mortality in DRC. That increased confidence, in turn, led us to make a larger grant that included provinces with estimated cost-effectiveness closer to our funding threshold.

Existing funding can’t cover nationwide campaigns

Our research for this grant found that despite the need, the available funding for DRC was insufficient to ensure that all areas had net campaigns. The Global Fund is the largest malaria funder in the world; it has a policy of providing no more than 10% of its malaria funding allocation to any one country. Due to this cap, limited funding from other donors, and the high burden of disease, there remains a significant need for nationwide campaigns that GiveWell’s support addresses.

We have high confidence in AMF’s ability to help fill this gap. GiveWell has funded net campaigns through AMF since 2012, and we know it is very experienced at procuring nets and supporting their delivery in DRC, where it has been working for more than a decade. We also spoke with government officials, staff from the organization that distributes the nets, and with other funders, all of whom told us that AMF is a welcome and constructive partner in DRC.

Why we’re funding more frequent net distributions

Because nets in DRC degrade quickly, we chose to fund more frequent net campaigns in up to five provinces where children are at higher risk of dying from malaria.[11] We expect campaigns in those areas to take place in 2027 and 2029, 24 months apart rather than 30 months.

In most countries with substantial malaria burden, nets are distributed every 36 months. Because field durability studies found that nets in DRC degrade more quickly, the DRC government aims to provide net campaigns every 30 months.[12] Our analysis of Demographic and Health Survey data also provided us with additional information about how long nets in DRC provide protection from malaria, supporting the earlier research that nets in DRC degrade as much as a year before they are replaced through new distributions.

We assessed net degradation by looking at how the number of children sleeping under nets changed over time, as we believe that this decline in net use is related to nets wearing out and no longer being usable. The net durability studies we have reviewed support this understanding, as does our analysis showing that the number of households owning a net decreases at a similar rate and direct data on net condition from AMF’s post-distribution monitoring. In the months immediately after a net campaign, we found that more than 80% of children under one year old slept under a net. By two years after a distribution, that number had declined to around 50%. And by three years after a campaign, predicted net use is approximately 20%, leaving children at much greater risk of contracting and dying from malaria.

How we’re increasing impact through research

For more than a decade, GiveWell has been at the forefront of malaria prevention, and the growing capacity and specialized expertise on our malaria team allowed us to expand that work even further through this grant. Our grant to support nets in DRC is just one part of our efforts to cost-effectively direct substantially more donor funding. We anticipate our total grantmaking is likely to approach or even exceed $1 billion this year, and we are working toward a future that could be several times that scale.

The intensive grant investigation process increased our confidence in the effectiveness of the nets, improved our understanding of how long nets provide protection, and reduced our uncertainty about malaria mortality in DRC, leading us to make a larger grant than we had in the past and to fund more frequent campaigns in some areas. We are excited about the increased impact we expect as a result of these changes and hope to publish more details about our grant investigation, including the full analysis we did of a prior DRC nets grant.

We appreciate the work that AMF, the implementing partners, and other funders supporting the DRC nets campaigns are doing to reduce the number of children who die from malaria in DRC. And we are especially grateful for the trust and generosity of our donors who make all of our grantmaking possible.