Seasonal malaria chemoprevention (SMC)—a program that provides preventive antimalarial medication to young children during the months when malaria is mostly likely to be transmitted—is one of the most cost-effective programs GiveWell has identified. Malaria Consortium’s SMC program has been one of our Top Charities since 2016, and we’ve recommended more than $500 million in grants to the program.

Most of our funding to date has supported programs in West Africa, where strong evidence gives us confidence in the effectiveness of the drug combination used. In eastern and southern Africa, malaria chemoprevention programs could potentially help many more children, but we have substantial uncertainties about drug effectiveness in that region.

In this episode, GiveWell CEO and co-founder Elie Hassenfeld speaks with Senior Researcher John Macke about the CHAMP trial, a randomized controlled trial of chemoprevention drugs we’re supporting in Malawi, and how it could shape our malaria grantmaking.

This research is one example of how GiveWell is building for the future: investing in research now that could substantially expand our ability to direct funding cost-effectively in the years ahead.

Elie and John discuss:

• Why eastern and southern Africa present different challenges: One of the drugs used in seasonal chemoprevention shows widespread resistance in the region, and existing trial evidence about the effectiveness of chemoprevention there has limitations. While we’ve supported SMC in parts of Uganda and Mozambique, we’ve been cautious about scaling up without stronger evidence on which drug combinations work and whether using certain drugs could increase resistance.
• What this trial will tell us: The trial will test three drugs alone and in different combinations across roughly 7,000 children in Malawi, making it the largest individually randomized trial of chemoprevention drugs ever conducted. We’ll learn about the efficacy of the two drugs currently used in SMC, as well as an additional drug that had previously shown resistance but might now be effective again. The trial will look at the effect of the drugs on both malaria infections and hospitalizations caused by malaria.
• How the results could affect our grantmaking: Depending on what we learn, this trial could open up more than $100 million in cost-effective funding opportunities for chemoprevention programs each year in eastern and southern Africa. The trial results will also provide a knowledge base for other funders and implementers to improve the cost-effectiveness of malaria programming. We expect initial results in mid- to late 2027, with the potential for resulting grants to provide medication to children in 2028-2029.

Visit our Top Charities Fund and All Grants Fund pages to learn more about how you can support this work, and listen or subscribe to our podcast for our latest updates.

This episode was recorded on January 22, 2026 and represents our best understanding at that time.