title: Vaccines, antibiotics, and atopy.
abstract: OBJECTIVE
  Early exposure to vaccines and antibiotics may increase the risk of developing atopy by protecting against infectious agents and reducing duration and severity of infections (the hygiene hypothesis). It may also shift the developing immune system towards a more allergic response. We assess possible associations in young allergy clinic patients.
  
  
  METHODS
  We conducted a case-control study of 6- to 16-year-old new allergy clinic patients who were skin tested for inhalant allergens during 1987-2001 and enrolled in KPNW since birth (n = 1074). Atopic cases had positive tests for at least one inhalant allergen. Non-atopic controls had negative tests for all inhalant allergens. Using logistic regression analysis, we estimated atopy odds ratios for vaccine and antibiotic exposure variables and associations between vaccine and antibiotic exposures during the first 2 years of life and subsequent new allergy diagnoses.
  
  
  RESULTS
  Atopy was not significantly associated with numbers of vaccine and antigen doses, or number of different antigens during the first 2 years of life. Number of antibiotic prescriptions was negatively associated with atopy risk. Neither exposure was significantly associated with risk of new allergy diagnoses in atopic children.
  
  
  CONCLUSIONS
  Atopy development appears to be unrelated to early vaccine exposure. Frequency of antibiotic prescriptions during early life, a proxy for infection frequency, appears to protect against allergic sensitization. Neither vaccines nor antibiotics appear to induce subsequent allergic reactions in atopic children.
authors.affiliation: Center for Health Research, Kaiser Permanente Northwest, Portland, OR 97227, USA. john.mullooly@kpchr.org
authors.forename: John P
authors.initials: JP
authors.lastname: Mullooly
authors.forename: Roberleigh
authors.initials: R
authors.lastname: Schuler
authors.forename: Michael
authors.initials: M
authors.lastname: Barrett
authors.forename: Julie E
authors.initials: JE
authors.lastname: Maher
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000485:Allergens / Q000276:immunology; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D002648:Child; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D006920:Hygiene; D006967:Hypersensitivity / Q000209:etiology* / Q000276:immunology*; D019570:Inhalation Exposure; D016015:Logistic Models; D008297:Male; D012307:Risk Factors; D012882:Skin Tests; D014612:Vaccines / Q000009:adverse effects*
chemical_list: D000485:Allergens; D000900:Anti-Bacterial Agents; D014612:Vaccines