title: Risk of Guillain-Barré syndrome following pandemic influenza A(H1N1) 2009 vaccination in Germany.
abstract: OBJECTIVE
  A prospective, epidemiologic study was conducted to assess whether the 2009 pandemic influenza A(H1N1) vaccination in Germany almost exclusively using an AS03-adjuvanted vaccine (Pandemrix) impacts the risk of Guillain-Barré syndrome (GBS) and its variant Fisher syndrome (FS).
  
  
  METHODS
  Potential cases of GBS/FS were reported by 351 participating hospitals throughout Germany. The self-controlled case series methodology was applied to all GBS/FS cases fulfilling the Brighton Collaboration (BC) case definition (levels 1-3 of diagnostic certainty) with symptom onset between 1 November 2009 and 30 September 2010 reported until end of December 2010.
  
  
  RESULTS
  Out of 676 GBS/FS reports, in 30 cases, GBS/FS (BC levels 1-3) occurred within 150 days following influenza A(H1N1) vaccination. The relative incidence of GBS/FS within the primary risk period (days 5-42 post-vaccination) compared with the control period (days 43-150 post-vaccination) was 4.65 (95%CI [2.17, 9.98]). Similar results were found when stratifying for infections within 3 weeks prior to onset of GBS/FS and when excluding cases with additional seasonal influenza vaccination. The overall result of temporally adjusted analyses supported the primary finding of an increased relative incidence of GBS/FS following influenza A(H1N1) vaccination.
  
  
  CONCLUSIONS
  The results indicate an increased risk of GBS/FS in temporal association with pandemic influenza A(H1N1) vaccination in Germany.
authors.affiliation: Division of Safety of Medicinal Products and Medical Devices, Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines, Langen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Prestel
authors.forename: Peter
authors.initials: P
authors.lastname: Volkers
authors.forename: Dirk
authors.initials: D
authors.lastname: Mentzer
authors.forename: Helmar C
authors.initials: HC
authors.lastname: Lehmann
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Hartung
authors.forename: Brigitte
authors.initials: B
authors.lastname: Keller-Stanislawski
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D016021:Epidemiologic Studies; D005260:Female; D005858:Germany / Q000453:epidemiology; D020275:Guillain-Barre Syndrome / Q000139:chemically induced*; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000009:adverse effects*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D019846:Miller Fisher Syndrome / Q000209:etiology; D011446:Prospective Studies; D012737:Sex Factors; D013997:Time Factors
chemical_list: D007252:Influenza Vaccines; C556153:pandemrix
keywords: Guillain-Barré syndrome; pandemic influenza vaccination; pharmacoepidemiology; self-controlled case series