Hygiene hypothesis: Early germ exposure prevents asthma?

content provided by mayoclinic.com

Hygiene hypothesis: Early germ exposure prevents asthma?


Does childhood exposure to germs help prevent asthma?

No name
No state given


Children growing up in rural areas, around animals and in larger families seem to develop asthma less often than do other children. According to the hygiene hypothesis, this is due to increased exposure to particular viruses, bacteria or parasites.

The hygiene hypothesis proposes that childhood exposure to germs and certain infections helps the immune system develop. This teaches the body to differentiate harmless substances from the harmful substances that trigger asthma. In theory, exposure to certain germs teaches the immune system not to overreact.

But preventing asthma isn't as simple as avoiding antibacterial soap, having a big family or spending time on the farm. For one thing, there are a number of microbes that may cause asthma rather than prevent it, such as respiratory syncytial virus (RSV). For another thing, infections that might help prevent asthma can cause a number of other health problems. The type of germs isn't the only factor that plays a role, either. The severity of an infection — and when it occurs during childhood — also appear to matter.

More research is needed to understand exactly how childhood germ exposure might help prevent asthma. What we do know is that in general, exposure to germs is likely to do more harm than good. Help your child avoid contacting or spreading germs with steps such as thorough hand washing, avoiding touching the eyes, nose or mouth, and covering the nose and mouth with a tissue when coughing or sneezing.

Last Updated: 2010-10-15
© 1998-2014 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.

Terms and conditions of use


Bookmark and Share   E-Mail Page   Printer Friendly Version