title: Incidence of new-onset autoimmune disease in girls and women with pre-existing autoimmune disease after quadrivalent human papillomavirus vaccination: a cohort study.
abstract: To assess whether quadrivalent human papillomavirus (qHPV) vaccination is associated with increased incidence of new-onset autoimmune disease in girls and women with pre-existing autoimmune disease.
  
  
  
  This register-based open cohort study included all girls and women between 10 and 30 years of age in Sweden in 2006-2012 diagnosed with at least one of 49 prespecified autoimmune diseases (n = 70 265). Incidence rate ratios were estimated for new-onset autoimmune disease within 180 days of qHPV vaccination using Poisson regression adjusting for, country of birth, parental country of birth, parental income and parental education.
  
  
  
  A total of 70 265 girls and women had at least one of the 49 predefined autoimmune diseases; 16% of these individuals received at least one dose of qHPV vaccine. In unvaccinated girls and women, 5428 new-onset autoimmune diseases were observed during 245 807 person-years at a rate of 22.1 (95% CI 21.5-22.7) new events per 1000 person-years. In vaccinated girls and women, there were 124 new events during 7848 person-years at a rate of 15.8 (95% CI 13.2-18.8) per 1000 person-years. There was no increase in the incidence of new-onset autoimmune disease associated with qHPV vaccination during the risk period; on the contrary, we found a slightly reduced risk (incidence rate ratio 0.77, 95% CI 0.65-0.93).
  
  
  
  In this nationwide study, qHPV vaccination was not associated with increased incidence of new-onset autoimmune disease in girls and women with pre-existing autoimmune disease.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: O
authors.initials: O
authors.lastname: Grönlund
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Herweijer
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Sundström
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Arnheim-Dahlström
mesh_terms: D000293:Adolescent; D000328:Adult; D001327:Autoimmune Diseases / Q000453:epidemiology*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D030361:Papillomavirus Infections / Q000517:prevention & control; D053918:Papillomavirus Vaccines / Q000008:administration & dosage*; D013548:Sweden / Q000453:epidemiology; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control; D014611:Vaccination; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines
keywords: autoimmune diseases; cohort study; epidemiology; infectious disease; vaccine