title: Tuberculosis infection notification in Swiss medical students during their clinical electives.
abstract: OBJECTIVE
  The aim of this study was to assess the tuberculin skin test conversion incidence in Swiss medical students.
  
  
  METHODS
  This was a prospective cohort study of medical students at the University of Zurich, using a standardized tuberculin skin test before and after clinical electives.
  
  
  RESULTS
  Two hundred and sixty-two students accepted the invitation to the pre-clerkship test, and 155 (59.2%) subjects were retested after an average period of 2.25 years. An increase of more than 10 mm in the transverse diameter of the induration in the retest compared to the baseline test was observed in 12 (7.7%) students. The annual conversion rate was 3.4% (95% CI 1.8-6.0%).
  
  
  CONCLUSIONS
  Even in an industrialized country, the risk of tuberculosis infection--as estimated by the tuberculin skin test--is substantial for health care professionals. Possible explanations for the high incidence and possible bias are discussed.
authors.affiliation: Institute for Social and Preventive Medicine, University of Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Turk
authors.forename: Felix
authors.initials: F
authors.lastname: Angst
authors.forename: Robert
authors.initials: R
authors.lastname: Steffen
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D017758:Infectious Disease Transmission, Patient-to-Professional; D008297:Male; D011446:Prospective Studies; D013337:Students, Medical; D011795:Surveys and Questionnaires; D013557:Switzerland / Q000453:epidemiology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission