School-age children typically have the highest intensity of worm infection of any age group. In addition, the most cost-effective way to deliver deworming pills regularly to children is through schools because schools offer a readily available, extensive and sustained infrastructure with a skilled workforce that is in close contact with the community.

With support from the local health system, teachers can deliver the drugs safely. Teachers need only a few hours training to understand the rationale for deworming, and to learn how to give out the pills and keep a record of their distribution.

Regular deworming contributes to good health and nutrition for children of school age, which in turn leads to increased enrolment and attendance, reduced class repetition, and increased educational attainment. The most disadvantaged children - such as girls and the poor - often suffer most from ill health and malnutrition, and gain the most benefit from deworming.

School-based deworming has its full impact when delivered within an integrated school health program that includes the following key elements of the FRESH (Focus Resources on Effective School Health) framework:

  • Health policies in schools that advocate the role of teachers in health promotion and delivery;
  • Adequate sanitation and access to safe water to reduce worm transmission in the school environment;
  • Skills-based health education that promotes good hygiene to avoid worm infection;
  • Basic health and nutrition services that include regular deworming.

Evidence that school deworming is beneficial and cost-effective:

1. Deworming contributes to Education for All

Studies in low-income countries of Africa, South America and Asia confirm that children with intense worm infections perform poorly in learning ability tests, cognitive function and educational achievement. Differences in test performance equivalent to a six- month delay in development can typically be attributed to heavier infections of the sort experienced by around 60 million school age children. Absenteeism is more frequent among infected than uninfected children: the heavier the intensity of infection, the greater the absenteeism, to the extent that some infected children attend school half as much as their uninfected peers. Deworming can benefit children's learning, substantially increase primary school attendance and significantly increase a child's ability to learn in school.

Deworming is an exceptionally low cost intervention. Operational research in Ghana and Tanzania has demonstrated that for the first five years of intervention, the average yearly cost of delivered treatment – taking into account current drug prices – is typically less than US $0.50 per child in an area where both schistosomiasis and the common intestinal worms are present, and less than US $0.25 per child in an area where only the latter are present. This is the total cost which includes training of teachers, as well as the procurement and distribution of drugs to students.

2. Deworming gives a high return to education and labour income

A randomized evaluation of school-based mass deworming for schistosomiasis and intestinal worms in Kenya found that absenteeism was reduced by one-quarter. Deworming was the most cost-effective method of improving school participation among a series of educational interventions. An extra year of primary schooling was gained for an investment of US $4 in deworming, as compared to US $38 to US $99 for other interventions.4 The Rockefeller hookworm control program early in the 20th century in the Southern USA achieved a similar reduction in absenteeism (23%) and long-run effects on labour income suggest the benefit of a hookworm-free childhood to be around 45% of adult wages. Deworming is therefore an efficient investment in human capital.

3. Deworming has major externalities for untreated children and the whole community

By reducing the transmission of infection in the community as a whole, deworming substantially improves health and school participation for both treated and untreated children, in treatment schools and in neighbouring schools. As a result, treating only school age children can reduce the total burden of disease due to intestinal worm infections by 70% in the community as a whole.7 These externalities are large enough to justify fully subsidizing treatment. They also explain why deworming is beneficial even without improvements in sanitation.

4. Deworming targets one of the most common, long-term infections of children in low-income countries

For girls and boys aged 5 to 14 years in low-income countries, intestinal worms account for an estimated 11 and 12 percent, respectively, of the total disease burden, and represent the single largest contributor to the disease burden of this group. An estimated 20 percent of disability adjusted life years lost because of communicable disease among school children is a direct result of intestinal worms.