Posted: August 23, 2017

Essential ingredients: a framework for STH control programming

By Grace Hollister, Evidence Action (STH Coalition partner)

Parasitic worm infection, or soil-transmitted helminthiasis (STH), is one of the most prevalent causes of illness among the world’s poorest and most vulnerable populations, especially children. Close to a quarter of the world’s population is infected with at least one STH species, and globally an estimated 870 million children are at risk of infection[1].

Intestinal worm infections cause a range of symptoms, including intestinal blood loss resulting in anemia, and impaired cognitive and physical development. Indeed, by interfering with nutrient uptake, worm infections undermine children’s health and ability to learn, preventing them from reaching their full potential.

Mass drug administration, long the cornerstone of STH control efforts, is the use of deworming drugs to treat an entire population in a given geographic area, regardless of each individual’s infection status. Deworming drugs are safe, efficacious, and available free of charge for school-age children through generous pharmaceutical donations coordinated by the World Health Organization (WHO). Treatment reduces morbidity, particularly in heavily-infected children, and is strongly associated with improved health, learning potential, and long-term productivity. However, to ensure these positive effects, treatment coverage must be sufficient and occur regularly.

The good news is that increased investments in STH control are paying off. Between 2011 and 2015 (the most recent year for which data is available), treatment coverage doubled among school-age children, reaching 63%.[2][3]And that progress has put within reach the target set by the World Health Organization: 75% treatment coverage for school-age children globally by the year 2020.

STH Coalition partners are contributing to this work in a variety of ways. In collaboration with country governments, they’re supporting school-based treatment programs, integrating deworming with other NTD treatments, and, in the case of preschool-age children, combining deworming with the provision of nutritional supplementation.

Still, lest this good news lead to complacency, consider that measures of progress at a global level mask variability among and within countries. Some countries have yet to scale their treatment programs to all at-risk areas, while others have fallen short of their coverage targets. In addition, many deworming treatments are effectively provided through the administration of albendazole as part of treatment for lymphatic filariasis (LF), given the overlap in drugs between the two diseases. Many countries are successfully reaching their LF elimination goals, meaning that as LF efforts stop, treatment gaps may emerge.

It’s imperative that these gaps are immediately addressed, and three key objectives can help us, as a community, maintain focus on the outcome of interest: reduced morbidity from worms for those who stand to lose the most when infected.

  • Ensure consistent drug treatment coverage and compliance within countries by strengthening and maintaining scaled programs.
  • Increase understanding of the impact of programs on morbidity control through regular parasitologic monitoring.
  • Develop a comprehensive framework for sustained control efforts, containing the essential ingredients to enable quality programming in all at-risk areas.

We propose that a framework for quality programming should include:

  • Evidence of what works: Findings from further operational and implementation-focused research must feed back into program strategy and decision-making to ensure an evidence-based approach is widely implemented.
  • A supportive policy environment: Programs backed by solid policies can maintain political support over time. Policies should extend beyond the health sector alone to engage education and environmental issues such as access to safe water and sanitation.
  • Standard practices and tools: Key tools for specific programmatic aspects including training, program monitoring, and evaluation support for program scale up. Standard processes and procedures can support replication of promising practices across many countries.
  • Tailored modalities: There is not a one-size-fits-all approach; multiple models from which countries can choose and adapt to the local context should be developed.
  • Common metrics and measurement methodologies: Key indicators and agreed methodologies will facilitate collection of high quality coverage and epidemiological data and encourage data sharing to monitor progress.
  • Technical capacity: Effective morbidity control efforts require the use of mathematical modelling and epidemiologic assessment to track the intensity of infection. Building this technical capacity may require training within countries that have achieved some success with mass drug administration.
  • Financial and human resources: A lack of financial resources can impede scale up, hence the need for continued support to sustain long-term treatment strategies. Domestic resources alone are insufficient.
  • Partnerships: Strong relationships within and between all stakeholders are needed to leverage resources and expertise for maximum impact.

Aligning partners on the framework their potential related roles can help to keep STH control on track to meet the 2020 goals – and most importantly to ensure that at-risk children receive the treatment they deserve to lead healthy, productive lives.



[1] World Health Organization. Soil-transmitted helminthiases: Situation and trends. Global Health Observatory data. 2015.
[2]Weekly Epidemiological Record Nos. 49/50, 2016, 91, 585-600
[3]Weekly Epidemiological Record No. 14, 2013, 88, 145-152