title: Correspondence (letter to the editor): Limitations.
authors.forename: Herbert
authors.initials: H
authors.lastname: Hof
authors.forename: Jan
authors.initials: J
authors.lastname: Bartel
mesh_terms: D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000517:prevention & control*; D003424:Crohn Disease / Q000453:epidemiology* / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D014611:Vaccination / Q000706:statistics & numerical data*