What are the long-term health effects of de-worming in childhood?

What is it about?

This study looks at how exposure to infectious diseases in childhood can affect health and lifespan later in life. I focus on hookworm, a parasitic infection that was once very common in the southern United States. Using historical records from the Rockefeller Sanitary Commission’s early 20th-century deworming campaign, I compared people who grew up in areas with higher versus lower hookworm exposure, before and after a major de-worming campaign. The analysis shows that children who received deworming treatment before age five lived longer as adults—gaining about 2.5 months of life on average—and also showed better health in midlife, with fewer allergies, lower inflammation, and stronger nutritional markers.

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Photo by Ivan Ivanovič on Unsplash

Photo by Ivan Ivanovič on Unsplash

Why is it important?

The findings provide rare long-term evidence on how reducing infectious diseases in early life shapes health decades later. Public health programs like mass deworming are often debated, with some suggesting that removing parasites might weaken immune systems (the so-called “hygiene hypothesis”). My results show the opposite: early-life deworming improved both lifespan and markers of immune function, while not leading to more allergies. This evidence strengthens the case for ongoing global deworming campaigns, particularly in low-income settings where parasitic infections remain widespread.

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