Deworming: What's the deal here?

By David Addiss 07 August 2015

Nursing student Mahammed-Ziad Ahmed administers deworming medication to a girl in Shinile Woreda, Ethiopia. Is the the growing investment in soil-transmitted helminthiasis control money well-spent? Photo by: Kat McDowell / U.S. Air Force / CC BY

In the past week, soil-transmitted helminthiasis has received a great deal of attention. This robust conversation was stimulated by the publication of another Cochrane Collaboration review on the benefits of mass deworming, and a series of articles in the International Journal of Epidemiology that featured a reanalysis of Miguel and Kremer’s 2004 article on the educational benefits of deworming.

These articles were followed by a flurry of blogs, tweets and opinion articles, many with a sensational angle. What can we make of all of this?

Despite the sensational headlines of late, a closer look at the actual scientific issues can reassure us that the growing investment in STH control is money well-spent.

The authors of the Cochrane review argue the benefits of deworming are not yet proven by randomized clinical trials. RCTs can provide strong evidence and we would all welcome more of them. However, unlike many scientists and certainly practicing physicians, the Cochrane Collaboration authors — academicians who are not responsible for public health programs — reject other types of scientific evidence as irrelevant.

Those of us who are public health practitioners rarely have the luxury of making decisions solely on the basis of RCTs. Public health practice and ethics demand that we consider the entire body of scientific evidence, which includes considerable knowledge resulting from studies other than RCTs. This evidence has found time and time again that the benefits of deworming are substantial.

In fact, even the authors of the Cochrane review agree that infected children should be dewormed. But testing and treating children one by one, especially those who live in low-resource settings, would be cumbersome and expensive. With such an approach, many of the children with the highest disease burden would go untreated. Mass deworming is the most cost-effective way to ensure that infected children receive much-needed treatment.

We call these intestinal worms “parasites” for good reason. They feed off their hosts — especially children living in communities where adequate nutrition and access to potable water sources and sanitation facilities are limited. These children need all the nutrition they can get to grow healthy and strong. They can scarcely afford to share the nutrients they receive with parasitic hitchhikers.

The good news overall is that interest and investment in STH control increased dramatically in the past few years. Nine donors met in April 2014 to launch what has become the STH Coalition. This initial group grew quickly; just over a year since launch, the coalition is now 39 members strong, and growing.

Commitment and momentum toward achieving the World Health Organization’s goals for STH control by 2020 are at an all-time high. The rapid growth and prominence of this movement to bring infection under control alone makes STH newsworthy.

Therefore, while we as a global community work to improve access to clean water, sanitation, hygiene and good nutrition, we must take full advantage of available medicines and distribution channels to move us closer to a world in which children can live without worms. This strategy, led by WHO, is endorsed by ministers of health from the nations of the world and supported by an increasingly diverse cross-sectoral group of partners who are committed to a vision of healthy children — without worms.

To read additional content on global health, go to Focus On: Global Health in partnership with Johnson & Johnson.

About the author

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David Addiss

Dr. David Addiss is the director of Children Without Worms, a program of the Task Force for Global Health in Decatur, Georgia, in the United States. For 20 years he worked on neglected tropical diseases as a medical epidemiologist at the U.S. Centers for Disease Control and Prevention. He has held positions in academia, migrant health, and philanthropy.


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