Q. Is dirt harmful? My husband wants to set up a sandbox for our two-year-old, but I am concerned that it could be full of dangerous germs, even if we cover it at night.
A. How complicated such a simple question can be! To answer this I turned to my allergy and immunology colleagues. Sandboxes in daycare centers have, on occasion, been found to have high levels of cat allergen.
The germs themselves are actually beneficial to the immune system and strengthen a child’s resistance to both infection and to allergies and asthma. This complicated theory has been called the hygiene hypothesis.
It speaks to the fact that some exposure to so-called germs is important to teach our immune systems to respond to infections and allergens in the environment.
There is obviously a balance of not wanting to have an unhealthy environment, such as when kids or animals use the sandbox as a bathroom! Also, food in the sandbox will encourage more harmful bugs. If one were going to be over-concerned, one would have to suspect that the sand on any public beach can be more concerning than that in a sandbox.