The Problem: Parasitic Worms​


While virtually nonexistent and unheard of in developed countries today, parasitic worm infections are endemic in many of the poorest countries in the world.

These infections, known as soil-transmitted helminths (STH) and schistosomiasis, interfere with nutrient uptake and can lead to anemia, malnourishment, and impaired mental and physical development. They pose a serious threat to children’s long-term health, education, and productivity. Infected children are often too sick or tired to concentrate at school, or to attend at all.

Worm infections disproportionately affect the poor. They are easily transmitted in areas with poor sanitation and open defecation. Children are particularly susceptible to infection and experience the greatest morbidity.

Parasitic worms exact an enormous toll on human capital, slowing economic development in parts of the world that can least afford it.

“A significant body of evidence shows that deworming works to improve children’s health, well-being, education, and long-term economic future.”

— World Health Organization (2016). WHO PCT Databank: Soil-transmitted Helminth Infections.

The Solution:
A Simple Treatment

To combat worm infection, regular treatment with a simple pill is universally recognized as a safe and effective solution. The Deworm the World Initiative supports school-based deworming: treatment delivered through existing education infrastructure, administered by teachers with support from the health system. This approach is highly cost-effective, well accepted by communities, and efficiently targets the population group at greatest risk for infection: children.

Rigorous evidence shows that school-based deworming can improve children’s health, education, and long-term productivity at an average cost of less than $0.50 per child per year.






Mass treatment of all children in at-risk areas avoids the need to screen individuals for infection, leading to dramatic cost savings, and drugs are safe even for uninfected children. The school-based approach builds upon the documented importance of convenience in preventative healthcare, by bringing treatment to where children already are.

The Deworm the World

The Deworm the World Initiative envisions a world where all at-risk children have improved health, increased access to education, and better livelihoods potential as a result of being free of intestinal worms. We work in close partnership with governments to enable elimination of intestinal worms as a public health problem.

  • We advocate for school-based deworming to policymakers, gaining and maintaining critical support amongst stakeholders responsible for children’s health and education.
  • We provide technical assistance to governments to launch, strengthen, and sustain high quality school-based deworming programs that leverage existing education and health infrastructure.
  • We employ an evidence-based approach to rigorously evaluate and learn from programs we support, iterating on program design alongside governments to maximize reach in a cost-effective manner.


Deworm the World Initiative: Partnership Model


We advocate with governments to launch deworming programs, and work collaboratively with ministries of health and education to establish effective policies and governance structures. We support alignment of school-based deworming with other health and education priorities to enable long-term political and resource commitments, and share global best practices to improve cost-effectiveness and results.


Guided by World Health Organization protocols, we work with epidemiologists and local partners to assess worm prevalence and intensity through field surveys. We use the survey results to support the development and implementation of appropriate treatment strategies. Once deworming programs are in place, we support governments to assess the impact of sustained mass treatment on worm infection.


We work closely with government partners to design their deworming program, develop operational plans and budgets, coordinate logistics, and provide on-the-ground support to ensure a high quality outcome.


We work with governments to develop locally appropriate campaigns that educate children and communities about the negative effects of worms, the importance of being dewormed, and behaviors to prevent infection. These campaigns increase acceptance and participation in deworming.


We support governments to design and coordinate an efficient multi-tier training and distribution cascade that is tailored to the local context, ensuring that knowledge and program materials are relayed from the national or state level all the way to the teachers responsible for administering deworming drugs.


We help governments evaluate appropriate treatment strategies, support drug procurement including through global pharmaceutical donation programs, and facilitate the development of robust protocols for tracking drug inventories and responding to adverse events.


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.


Watch the video below to learn more about our work:

Our Impact

Our results at a glance 

  • In 2019, the Deworm the World Initiative supported governments to treat more than 280 million children in India, Kenya, Nigeria, Ethiopia, and Pakistan.
  • We support India’s National Deworming Day, which targets all children ages 1-19 at schools and preschools; in 2019 the program treated more than 255 million children.
  • With our technical assistance, Kenya’s National School-Based Deworming Program has consistently treated over 6 million children per year since 2012, dramatically reducing STH and schistosomiasis infection.
  • Since 2013, GiveWell has named the Deworm the World Initiative one of its top-rated charities.



What’s next

The Deworm the World Initiative has ambitious plans to help eliminate the public health problem of parasitic worms in the coming years. Alongside evolving our technical assistance to existing government partners to meet their needs, we are leveraging opportunities to accelerate treatment coverage for at-risk children, with a focus on high-need countries like Pakistan and Nigeria.

 We will:

  • Decrease the worm burden by expanding high-quality school-based deworming into new geographies
  • Build sustained government capacity to operate consistent, cost-effective, and high-quality school-based deworming programs
  • With partners, drive further progress towards achievement of the WHO target of STH treatment for 75% of at-risk children by 2020

The Evidence for Deworming

The evidence for mass school-based deworming

Parasitic worms are debilitating, widespread, and under-treated. School-based deworming is safe, cost-effective and scaleable. There is a robust evidence base for the work the Deworm the World Initiative undertakes.

Deworming has important impacts on school participation, cognition and nutrition, and future earnings. Multiple rigorous studies have shown strong evidence of the effects of deworming, providing confidence in the benefits of treatment. We summarize the evidence base for mass school-based deworming in this post.

School Participation

Parasitic worms limit educational outcomes for children. Not only are infected children less likely to be enrolled in school, but they are also less likely to attend school and more likely to perform lower on testing.

  • A long-term follow-up study linking aggregate infection data with individual socioeconomic data from the southern US in the 1910s found that a non-infected child was 20 percentage points more likely to be enrolled in school than an infected child, and was also 13 percentage points more likely to be literate.

  • Miguel and Kremer’s experimental evaluation in Western Kenya found that deworming treatment resulted in a 25% decrease in absenteeism at treatment schools.

  • In a long-term follow-up study in Kenya, evidence shows that among females, deworming increased the rate of passing the national primary school exit exam by 9.5 percentage points on a base of 41%.

Nutrition and Cognition

Children with parasitic worms suffer from nutritional impairment, impacting their growth and physical development. Deworming treatment leads to significant weight gains and allows more energy to be focused on growth and development.

  • A meta-analysis authored by Croke et al. (2016) finds a substantial and highly robust positive effect on child weight resulting from deworming. The effects are particularly large in areas with at least 20% prevalence; this is the same threshold at which the WHO currently recommends mass treatment.
  • A randomized controlled trial in Uganda 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.
  • Deworming has positive externalities even for children who are not directly treated. Owen Ozier’s 2016 study finds that younger siblings of children who were treated show cognitive gains comparable to between 0.5 and 0.8 years of schooling ten years later.

Why Mass Treatment

  • Is mass treatment justified? On cost-effectiveness grounds we believe that it clearly is, as the cost of screening is four to ten times that of the treatment itself. Everyone agrees that children infected with worms should be treated. Because the drugs are very effective in treating worms, and are safe even for the uninfected, the WHO recommends mass drug administration as the clinical standard of care in areas where more than 20% of children are infected.
  • Deworming through schools, and preschools in some areas, provides the greatest opportunity to reach a high proportion of the at-risk population while minimizing costs through the use of existing infrastructure.

Where We Work

Where we work


  • India is the country with the highest number of worm infections globally; 220 million children at risk for STH infections.
  • We provide technical assistance to the Ministry of Health and Family Welfare along with customized assistance to eleven states: Bihar, Chattisgarh, Haryana, Jharkhand, Madhya Pradesh, Rajasthan, Telangana, Tripura, Uttarakhand, Uttar Pradesh, and Karnataka.
  • In February 2015, we helped the national government initiate National Deworming Day (NDD). The program reach extends to preschools, government schools, private schools, and out-of-school children, targeting all children aged 1-19. As of February 2019, NDD scaled up to 34 states and union territories, with the government reporting treatment of over 221 million children.


  • In Kenya, more than 5 million school-age children are at risk of intestinal parasitic worms, including STH and schistosomes.
  • We have supported the Government of Kenya’s school-based deworming at national scale since 2012, annually treating children at risk for STH and schistosomiasis through a collaboration between the Ministry of Education and Ministry of Health. In 2018, the program treated 6.3 million children (including 521,643 for schistosomiasis) across 27 counties. The program reached 81% of at-risk children, exceeding the WHO’s 75% coverage target.
  • Across the 27 counties, STH infections have steadily reduced, from baseline infection of 33.4% to 15.9% after three years of treatment (including a 19% reduction in moderate-to-heavy intensity infections); schistosomiasis infection reductions have also been achieved.


  • Ethiopia is the fifth most burdened country globally by childhood worm infection; 18.4 million school-age children and 6.6 million preschool-age children are at risk for STH infection. Approximately 14.6 million school-age children are at risk of schistosomiasis.
  • The national deworming program is led by the Federal Ministry of Health, and implemented in partnership with the Ministry of Education and the Ethiopian Public Health Institute. We partner with the Schistosomiasis Control Initiative (SCI) to provide technical assistance to national and sub-national government ministries.
  • Through 2018, the Government of Ethiopia treated roughly 15.4 million school-age children children for STH and 6.5 million for schistosomiasis. 
  • We will continue to support discrete pieces of work related to Ethiopia’s Technical Advisory Group for STH and SCH, as well as remain aware of evolving partnership and support needs in Ethiopia, to weigh any potential reasons for our level of involvement to change.


  • Nigeria is the third most burdened country in terms of its number of children at risk for worm infections. Approximately 28.6 million school-age children are at risk for STH infection; 23.8 school-age children are at risk of schistosomiasis.
  • We partner with Cross River state and RTI International to provide technical assistance to the State Ministries of Health and Education; our support for school-based treatment complements community-based treatment of other neglected tropical diseases. In 2018, the program treated over 580,000 school-age children for STH and schistosomiasis.
  • We are engaging with the Federal Ministry of Health to support development of a national-level deworming strategy and collaborating on further expansion of school-based deworming in Nigeria. In 2018, our state level support expanded to three additional partner states – Rivers, Oyo, and Ogun – and treated 2.2 million children.


  • In Vietnam, we partnered with Thrive Networks to provide technical assistance to the Government of Vietnam’s deworming program in four provinces.
  • In November 2018 the program treated over 794,000 children, achieving over 95% coverage.
  • We also conducted a randomized controlled trial (RCT) to understand whether a school-based hygiene education package is successful and cost-effective at reducing reinfection among school-age children when combined with school-based deworming. 
  • Our partnership with Thrive Networks formally came to an end on March 31, 2019, closing out our deworming work in Vietnam. National stakeholders indicated that the newly revised national guidelines for deworming — revisions that were made based on strong advocacy from our program — will be applied for all endemic provinces going forward. They also expressed a willingness to develop a long-term strategy for STH control in Vietnam.


  • In 2016 we worked with our partner, Interactive Research & Development (IRD), in coordination with provincial governments in Pakistan, to carry out the country’s first national-level STH survey to map worm prevalence and intensity.
  • Data collected from the survey revealed an estimated 17 million school-age children require annual treatment for STH.
  • Working with health and education stakeholders at the national and provincial level we supported the initiation of a school-based deworming program,  continuing our partnership with IRD. The first round of treatment occurred in February of 2019 in ICT (treating 110,000 children) and there are plans for expanding treatment into other provinces in late 2019 and early 2020.

Learn More

Learn more about the Deworm the World Initiative in the blog posts below.

Vietnam is Now Successfully Conducting Deworming Without Us

In 2014, we partnered with Thrive Networks, with funding from Dubai Cares, to support the Government of Vietnam’s school-based deworming program. We tailored our approach to the government’s needs: support to improve the delivery, reach, and monitoring of their program in ways that would enhance already significant coverage and cost-effectiveness, while bolstering confidence in its impact. Vietnam is now successfully conducting deworming without us.

Read More →

Leveraging Our Existing Government Partnership in India to Tackle Anemia

For several years, we’ve partnered with the Government of India to deliver mass school-based deworming as part of our Deworm the World Initiative. The ongoing success of this partnership has allowed us to explore opportunities to extend our impact in India. Ultimately, we settled on one promising area for further exploration through our Beta incubator: India’s national Weekly Iron and Folic Acid Supplementation (WIFS) program, which is designed to address the pressing challenge of anemia among school-age children.

Read More →

School-based Deworming: A Low-Cost Intervention Achieving High-Impact Benefits

There is a difference between a low-cost program and a cost-effective program. Implementing a low-cost program is not sufficient – we want to ensure that the impacts of the program are measurable and that the benefits outweigh the costs – this is what makes a program truly cost-effective. Putting these two parts of the equation – costs and benefits – together, we can estimate the value for money of our program.  

Read More →

Expanding Deworming to Migrant Populations in India under National Deworming Day

India’s National Deworming Day (NDD), initiated in 2015, is the world’s largest single-day public health intervention, providing children between the ages of 1-19 with free deworming tablets. As part of Evidence Action’s technical assistance to the Government of India and select state governments for the August NDD treatment round, we are collaborating on several tailored strategies to target hard-to-reach children, including migrant workers in the north-eastern state of Tripura.

Read More →


Last Call for COVID-19: Combating the Pandemic in Rajasthan

The Indian state of Rajasthan asked for our assistance in identifying elderly members of the community who were immunocompromised, had preexisting conditions, or presented any other factors that increased their risk of contracting COVID-19.

How Evidence Action is Supporting the Government of India’s Response to COVID-19

In India, Evidence Action supports national and state governments to deliver high-impact, cost-effective health interventions at scale. Due to India’s lockdown measures, which include large-scale school closures, school-based programs are unlikely to resume in the near-term. We are therefore working to determine how best to support the rapid recovery of these programs once schools reopen, while simultaneously leveraging the capacity of our team in India to assist our government partners in managing COVID-related challenges.

Vietnam is Now Successfully Conducting Deworming Without Us

In 2014, we partnered with Thrive Networks, with funding from Dubai Cares, to support the Government of Vietnam’s school-based deworming program. We tailored our approach to the government’s needs: support to improve the delivery, reach, and monitoring of their program in ways that would enhance already significant coverage and cost-effectiveness, while bolstering confidence in its impact. Vietnam is now successfully conducting deworming without us.

Now More Than Ever, Safe Water – and Safe Hygiene Practices – Are Essential

With each passing day, the COVID-19 pandemic continues to bend health systems to their breaking points, and organizations like ours are keenly focused on the looming threat that this pandemic presents to low- and middle-income countries. At Evidence Action we are seeking to leverage our existing resources and relationships to support these governments and communities in their response to COVID-19.

Our Response to the COVID-19 Pandemic

At Evidence Action we are actively managing the unprecedented set of risks and challenges posed by COVID-19 to the communities and people we serve. In such circumstances, provision of basic services becomes even more essential, to avert easily preventable disease and avoid further burdening fragile health systems.

Harnessing Dispensers for Safe Water’s Contribution to Managing Climate Change

When we launched Dispensers for Safe Water, we had a bold vision: deliver safe water access through a self-sufficient program. While we’re still a long way from a self-funded program, last year, the UNFCCC approved our largest consignment of carbon credits to date. Carbon funds provide an important leverage opportunity for the program’s donor funding – and contribute to our ability to provide safe water to over 4 million people.