Health

Deworm the World

Research summary, last reviewed May 2026. Evidence Action, Inc., US 501(c)(3), EIN 90-0874591. Official site.

Independent recognition: GiveWell-supported since 2013 · Founders Pledge recommended · The Life You Can Save recommended · Giving What We Can recommended · Effektiv Spenden recommended · Charity Navigator 4/4 stars (98%)

Headline outcome: More than 2 billion treatments delivered since 2014, at around USD 0.50 per child per year

What does Deworm the World do?

Deworm the World is a programme run by the charity Evidence Action. It provides technical assistance to governments so they can deliver school-based mass treatment for intestinal worms at national scale. Rather than buying and handing out medicine itself, Deworm the World trains the teacher and health-worker cascades, designs the procurement and monitoring, runs coverage surveys, and helps run the community campaigns that make a deworming day work.

The medicine, albendazole, is a single dose that safely expels the most common intestinal worms, and the World Health Organization recommends treating whole age-eligible populations wherever local prevalence is above 20%, without individual screening. Because the treatment is delivered through the government’s own existing teacher and health workforce, the cost is exceptionally low, around USD 0.50 per child per year.

The programme grew out of a landmark Kenyan trial by Michael Kremer and Edward Miguel and was scaled into Evidence Action when it spun out of Innovations for Poverty Action in 2013. Its best-known campaign, in Bihar, India in 2011, dewormed 17 million children across more than 67,000 schools. Cumulatively it has delivered more than 2 billion treatments since 2014, including 198 million children in 2024 alone.

Why did EveryDrop choose it?

Deworm the World passed our four-stage vetting assessment, mapped to the advancement of health and the saving of lives, with an education benefit through improved school attendance. Treatment is universal and free at the point of use, targeted only by objective prevalence and age criteria, so there is no prejudicial selection.

Its parent charity has one of the cleanest governance profiles in our set. The most recent Form 990 affirms every required governance policy, answers all related-party disqualifier questions “No”, carries an unqualified audit opinion, and shows executive pay within sector norms. It holds a 4-star Charity Navigator rating (98%) and is recommended by an unusually deep bench of independent evaluators, including GiveWell, which has supported it continuously since 2013, Founders Pledge, The Life You Can Save, Giving What We Can and Effektiv Spenden.

How effective is it?

GiveWell puts the total cost per treatment between USD 0.35 in India and USD 0.66 in Kenya. Its September 2025 retrospective of the India programme estimated cost-effectiveness “plausibly around” its threshold of roughly 10 times its cash-benchmark, while being candid about wide confidence intervals and lessons learned about baseline data collection. GiveWell is highly confident that deworming reduces worm loads in children; the underlying parasitology is not in serious dispute.

What are the open questions?

We publish what we are monitoring as well as what we like. The honest debate here, sometimes called the “Worm Wars”, is about how large the longer-run benefits of mass deworming are, not whether the treatment helps. A 2015 reanalysis weakened the original schooling result under alternative assumptions, and a Cochrane review found substantial evidence of no measurable benefit when treating whole populations on outcomes such as cognition and school performance. A 2024 meta-analysis reaffirmed significant positive effects on child weight and growth where prevalence is above the WHO threshold. GiveWell itself discounts the long-run effects heavily and still recommends the programme, because even discounted benefits, combined with the very low cost, remain attractive.

Evidence Action engages with critics openly, publishing a summary of the evidence base and submitting to evaluations that revised its estimates downward. It is also managing geographies responsibly: the Kenya programme is in a final year of support, work in Malawi is winding down, and the Indian state programmes are expected to become self-sufficient by March 2027. A chief-executive transition is underway, which we will re-check at the next annual review.

Sources

This summary is derived from EveryDrop's internal vetting dossier, prepared under our four-stage assessment framework using public, verifiable sources. Assessments are re-checked every twelve months. If you spot something we should know, email [email protected].