Bugging Asthma

Minor infections picked up in day care may keep kids from developing the disease. Here's why

It's called the "Hygiene Hypothesis," and researchers invoke it to try to explain why the number of children who develop asthma has grown so dramatically over the past three decades. Bolstered by a handful of studies, the basic idea is that modern urban society is too clean for the kids' own good. A hundred years ago, children's immune systems would have faced all kinds of bacterial and viral infections. Today those immune systems don't know what to do in our supersanitized environment, so they wind up attacking pollen, dust mites and other usually innocuous substances instead. In the worst cases, a...

Want the full story?

Subscribe Now


Learn more about the benefits of being a TIME subscriber

If you are already a subscriber sign up — registration is free!