Deworm the World Initiative

The Evidence For Deworming 

Intestinal worms are debilitating, widespread, and under-treated. School-based deworming is safe, cost-effective and scale-able. What is the evidence base for the work that  the Deworm the World Initiative undertakes? 

We have detailed summary of the evidence base for mass school-based deworming programs in this post. Here are key findings:

School participation

Future earnings

  • Hookworm infections could have explained as much as 22% of the income gap between the U.S. North and South.
  • In Kenya, men who were treated as children worked 3.4 more hours per week, spent more time in entrepreneurial activities, and were more likely to work in higher-wage manufacturing jobs. This long-term impact study in Kenya calculates a rate of return for governments who invest in deworming of 32-52%.

Cognition and nutrition

  • A great deal of our deworming work is in India, where we support a government-led program that provides iron supplementation in addition to deworming. A randomized health intervention that provided iron, Vitamin A and deworming drugs to Indian preschool children in the slums of Delhi found a significant gain in child weight and school participation compared to intervention with Vitamin A alone. Absenteeism was reduced by one-fifth in the treatment group. We do note, however, that the large DEVTA trial found no impacts of deworming or Vitamin A supplementation on mortality in a rural area where worm loads were light. We prioritize, and urge our government partners to prioritize, investment in areas where worm loads are high.
  • Owen Ozier’s study on the long-term effects of early childhood deworming suggests that reduced exposure to worm infections may improve cognition for children less than one year of age. These young children in the catchment area of treatment schools showed large gains on cognitive tests about ten years later.
  • A randomized controlled trial in Uganda (Alderman and colleagues, 2006), less well known than the Kenya trial, perhaps, but similar in many ways, finds that the provision of periodic anthelmintic treatment as a part of child health services resulted in an increase in weight gain of about 10% above expected weight gain when treatments were given twice a year, and an increase of 5% when the treatment was given annually.
  • Chronic infections in childhood (from diarrhea, to malaria, to worms) generate inflammatory (immune defense) responses lead substantial energy to be diverted from growth. There are interaction effects too, with deworming, for example, making it easier to fight off malaria.
  • More generally, in their summary of deworming, the WHO points to several channels by which worms may impair nutrition, and notes several studies that can support these claims.

  Mass treatment vs. screening? 

  • Is mass treatment justified? On cost-effectiveness grounds we believe that it clearly is, as the cost of treatment is cheaper than individual screening. The WHO states that the cost of screening is four to ten times that of the treatment itself. Because the drugs are very safe and has no side effects for the uninfected, the WHO does not recommend individual screening. The WHO instead recommends mass drug administration in areas where more than 20% of children are infected.

  • We have found that deworming through schools provides the greatest opportunity to reach the entire at-risk population while minimizing costs through the use of existing government infrastructure.

Scaling School-Based Deworming 

The Deworm the World Initiative enables governments to eliminate the public health threat of worms through school-based mass deworming programs. 

More specifically, Evidence Action advocates for school-based deworming to policymakers and provides technical assistance to launch, strengthen and sustain school-based deworming programs. We work directly with governments to rapidly scale programs targeting all at-risk school-age children.

We currently work in Kenya, India, Ethiopia, and Vietnam. 

What Does the Deworm the World Initiative Do?

1.Policy and Advocacy with Governments

We advocate with governments to launch deworming programs, then work collaboratively with them to establish effective policies and long-term commitment by building their capacity, mobilizing domestic support and sharing knowledge about improving cost-effectiveness and results.

2.Prevalence Surveying and Mapping

We work with epidemiologists and local partners to assess worm prevalence and intensity, obtaining data to develop a targeted treatment strategy and to determine parasitological impact once programs are in place.

3.Program Planning and Management

We work closely with the Ministries of Education and Health to design a program with joint ownership, develop operational plans and budgets, coordinate logistics, and provide on-the-ground support to ensure a high quality outcome.

4.Public Awareness and Mobilization

We work with governments and communications experts to design locally appropriate awareness campaigns to communicate messages through a wide variety of channels to increase public acceptance and effectiveness of deworming programs. 

5. Monitoring and Evaluation

We help governments design monitoring systems to measure effectiveness in achieving intended program results. We also conduct independent monitoring to validate program results, and evaluate the impact of programs in reducing worm prevalence and intensity.

6.Training and Distribution Cascade

We consistently design and support training through an efficient multi-tier cascade approach that is tailored to the local context,ensuring knowledge reaches from the national level all the way to the teachers responsible for administering deworming medication.

7.Drug Management and Coordination

We help governments evaluate appropriate drug treatment strategies and dosage, support drug procurement including through global pharmaceutical donation programs, and design robust serious adverse event protocols and drug tracking systems.




Where We Work

Bihar State, India 

  • The largest school-based deworming program in the world to date. 
  • A partnership between the Government of Bihar’s State Health Society Bihar, Bihar Education Project Council, and Evidence Action.
  • 1st deworming round in 2011 reached 17 million children.
  • 2nd round in 2012 treated 16.3 million across 69,376 government schools. 500,000 of treated children were non-enrolled, a population that is typically more difficult to reach.
  • 3rd round of deworming took place in 2014 with 85% of target age group children or 16.2 million children dewormed. This included 736,000 non-enrolled children.

Delhi State, India 

  • 1st in 2012 round treated 2.65 million children across 2400 schools and 8200 anganwadis (preschools), or 73% of all children in Delhi.
  • 2nd round in 2013 reached 2.38 million children. 
  • Deworming in Delhi is implemented through the Weekly Iron and Folic Acid Supplement Program in collaboration with Government of Delhi (Department of Health and Family Welfare, Department of Education, Department of Women and Child Development, Municipal Corporation of Delhi, the New Delhi Municipal Corporation, the Cantonment Board of Delhi, and Evidence Action.

Rajasthan State, India 

  • 1st round in 2012 reached 10.8 million school-age and preschool-age children through 79,000 schools and 59,000 anganwadis
  • 2nd round in 2013 treated 10.8 million children.
  • The Government of Rajasthan’s Departments of Education, Medical Health and Family Welfare, and Women and Child Development, with Evidence Action and UNICEF jointly implement this program.


  • Kenya’s National School-Based Deworming Program started in 2009. In 2012, it expanded to a nationwide program aimed at treating all at-risk Kenyan children each year for at least five years.
  • Implemented by the Ministry of Education, Science, and Technology and the Ministry of Health.
  • With support of Evidence Action’s Deworm the World Initiative, the Government of Kenya successfully reached 5.9 million preschool and school-age children in 2012/13 and 6.4 million children in 2013/14, surpassing targets by 18% and 12% respectively. School year 2014/15 results will be released in October. Technical and operational assistance to the program will continue through 2017.