title: Lack of association of Guillain-Barré syndrome with vaccinations.
abstract: BACKGROUND
  Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy, thought to be an autoimmune process. Although cases of GBS have been reported following a wide range of vaccines, a clear association has only been established with the 1976 H1N1 inactivated influenza vaccine.
  
  
  METHODS
  We identified hospitalized GBS cases from Kaiser Permanente Northern California (KPNC) from 1995 through 2006. The medical record of each suspected case was neurologist-reviewed according to the Brighton Collaboration GBS case definition; only confirmed cases were included in the analyses, and cases of Miller Fisher syndrome were excluded. Using a case-centered design, we compared the odds of vaccination in the 6 and 10 weeks prior to onset of GBS to the odds of vaccination during the same time intervals in all vaccinated individuals in the entire KPNC population.
  
  
  RESULTS
  We confirmed 415 incident cases of GBS (including Brighton levels 1, 2, and 3) during the study period (>30 million person-years). Incidence peaked during the winter months. The odds ratio of influenza vaccination within a 6-week interval prior to GBS, compared with the prior 9 months, was 1.1 (95% confidence interval [CI], .4-3.1). The risk in the 6-week interval compared to the prior 12 months for tetanus diphtheria combination, 23-valent pneumococcal polysaccharide, and for all vaccines combined was 1.4 (95% CI, .3-4.5), 0.7 (95% CI, .1-2.9), and 1.3 (95% CI, .8-2.3), respectively.
  
  
  CONCLUSIONS
  In this large retrospective study, we did not find evidence of an increased risk of GBS following vaccinations of any kind, including influenza vaccination.
authors.affiliation: Kaiser Permanente Vaccine Study Center, Oakland, CA 94612, USA. roger.baxter@kp.org
authors.forename: Roger
authors.initials: R
authors.lastname: Baxter
authors.forename: Nandini
authors.initials: N
authors.lastname: Bakshi
authors.forename: Bruce
authors.initials: B
authors.lastname: Fireman
authors.forename: Edwin
authors.initials: E
authors.lastname: Lewis
authors.forename: Paula
authors.initials: P
authors.lastname: Ray
authors.forename: Claudia
authors.initials: C
authors.lastname: Vellozzi
authors.forename: Nicola P
authors.initials: NP
authors.lastname: Klein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D020275:Guillain-Barre Syndrome / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014611:Vaccination / Q000009:adverse effects*; D055815:Young Adult
keywords: Guillaine-Barré syndrome; immunizations; influenza; safety; vaccine