title: Routine vaccination against pertussis and the risk of childhood asthma: a population-based cohort study.
abstract: BACKGROUND
  In industrialized countries vaccination coverage remains suboptimal, partly because of perception of an increased risk of asthma. Epidemiologic studies of the association between childhood vaccinations and asthma have provided conflicting results, possibly for methodologic reasons such as unreliable vaccination data, biased reporting, and reverse causation. A recent review stressed the need for additional, adequately controlled large-scale studies.
  
  
  OBJECTIVE
  Our goal was to determine if routine childhood vaccination against pertussis was associated with subsequent development of childhood wheezing disorders and asthma in a large population-based cohort study.
  
  
  METHODS
  In 6811 children from the general population born between 1993 and 1997 in Leicestershire, United Kingdom, respiratory symptom data from repeated questionnaire surveys up to 2003 were linked to independently collected vaccination data from the National Health Service database. We compared incident wheeze and asthma between children of different vaccination status (complete, partial, and no vaccination against pertussis) by computing hazard ratios. Analyses were based on 6048 children, 23 201 person-years of follow-up, and 2426 cases of new-onset wheeze.
  
  
  RESULTS
  There was no evidence for an increased risk of wheeze or asthma in children vaccinated against pertussis compared with nonvaccinated children. Adjusted hazard ratios comparing fully and partially vaccinated with nonvaccinated children were close to one for both incident wheeze and asthma.
  
  
  CONCLUSIONS
  This study provides no evidence of an association between vaccination against pertussis in infancy and an increased risk of later wheeze or asthma and does not support claims that vaccination against pertussis might significantly increase the risk of childhood asthma.
authors.affiliation: Institute of Social and Preventive Medicine, Finkenhubelweg 11, CH-3012 Bern, Switzerland.
authors.forename: Ben D
authors.initials: BD
authors.lastname: Spycher
authors.forename: Michael
authors.initials: M
authors.lastname: Silverman
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
authors.forename: Marcel
authors.initials: M
authors.lastname: Zwahlen
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Kuehni
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D016667:Bacterial Capsules / Q000008:administration & dosage / Q000009:adverse effects; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000009:adverse effects*; D004739:England; D005260:Female; D005500:Follow-Up Studies; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000009:adverse effects; D006306:Health Surveys; D006801:Humans; D007223:Infant; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage / Q000009:adverse effects; D016016:Proportional Hazards Models; D012135:Respiratory Sounds / Q000209:etiology; D012306:Risk; D012959:Socioeconomic Factors
chemical_list: D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D022542:Measles-Mumps-Rubella Vaccine