Statistical analysis of the effects of free deworming treatment in the first 2 treated schools in 1998-1999 indicate that treatment substantially improved student attendance and health. The program also had significant "spillover" effects, improving health outcomes and attendance among students in neighboring primary schools. We arrive at these figures by comparing outcomes in the three groups of schools, which were phased into de-worming in different years. The randomized order of deworming treatment phase-in allows us to isolate the impact of deworming from other factors that may affect child health and education.

• Deworming reduced serious worm infections in children by one half. 

• Students who received treatment reported being sick significantly less often, had lower rates of severe anemia, and showed substantial height gains. The average height gain in treatment schools was roughly 0.5 centimeters.

• When younger children were dewormed, they attended school 15 more days per year, while older children attended school approximately 10 more days per year.

• The entire community around each school, and those living up to 6 kilometers away, benefited from deworming through a phenomenon known as "spillover". Even those who aren't treated benefit because deworming children reduces transmission to other community members. Students at neighboring schools attended school an average of 3-4 additional days per year. Although we did not collect data on adults, it is also likely that older community members were able to work more days as a result of spillover effects.

• Including the spillover benefits of treatment, the cost of keeping a child in school one additional day is only US$0.02, which makes deworming considerably less expensive than any alternative method of increasing primary school participation.

Given the great success of this project, IPA is now working to Scale Up school-based deworming through the Deworm the World initiative.  Visit Deworm the World for more information.