The hygiene hypothesis revisited

Immunol Allergy Clin North Am. 2005 May;25(2):247-62, v-vi. doi: 10.1016/j.iac.2005.03.005.


The original hygiene hypothesis proposed that reductions in family size and exposure to childhood infections were responsible for the rise in atopic diseases. Numerous epidemiologic and longitudinal studies have been performed to test this hypothesis, which has evolved in response to these findings and emerging concepts related to the innate immune response and immunoregulatory mechanisms. Collectively, these advances raise hope that the concepts espoused in original hygiene hypothesis may soon lead to new preventive approaches to atopic diseases.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Allergens / immunology
  • Animals
  • Anti-Bacterial Agents
  • Asthma / etiology
  • Endotoxins / physiology
  • Humans
  • Hygiene*
  • Hypersensitivity / epidemiology
  • Hypersensitivity / genetics
  • Hypersensitivity / immunology*
  • Infections / immunology
  • Vaccination


  • Allergens
  • Anti-Bacterial Agents
  • Endotoxins