title: International collaboration to assess the risk of Guillain Barré Syndrome following Influenza A (H1N1) 2009 monovalent vaccines.
abstract: BACKGROUND
  The global spread of the 2009 novel pandemic influenza A (H1N1) virus led to the accelerated production and distribution of monovalent 2009 Influenza A (H1N1) vaccines (pH1N1). This pandemic provided the opportunity to evaluate the risk of Guillain-Barré syndrome (GBS), which has been an influenza vaccine safety concern since the swine flu pandemic of 1976, using a common protocol among high and middle-income countries. The primary objective of this project was to demonstrate the feasibility and utility of global collaboration in the assessment of vaccine safety, including countries both with and without an established infrastructure for vaccine active safety surveillance. A second objective, included a priori, was to assess the risk of GBS following pH1N1 vaccination.
  
  
  METHODS
  The primary analysis used the self-controlled case series (SCCS) design to estimate the relative incidence (RI) of GBS in the 42 days following vaccination with pH1N1 vaccine in a pooled analysis across databases and in analysis using a meta-analytic approach.
  
  
  RESULTS
  We found a relative incidence of GBS of 2.42 (95% CI 1.58-3.72) in the 42 days following exposure to pH1N1 vaccine in analysis of pooled data and 2.09 (95% CI 1.28-3.42) using the meta-analytic approach.
  
  
  CONCLUSIONS
  This study demonstrates that international collaboration to evaluate serious outcomes using a common protocol is feasible. The significance and consistency of our findings support a conclusion of an association between 2009 H1N1 vaccination and GBS. Given the rarity of the event the relative incidence found does not provide evidence in contradiction to international recommendations for the continued use of influenza vaccines.
authors.affiliation: Department of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. c.dodd@erasmusmc.nl
authors.forename: Caitlin N
authors.initials: CN
authors.lastname: Dodd
authors.forename: Silvana A
authors.initials: SA
authors.lastname: Romio
authors.forename: Steven
authors.initials: S
authors.lastname: Black
authors.forename: Claudia
authors.initials: C
authors.lastname: Vellozzi
authors.forename: Nick
authors.initials: N
authors.lastname: Andrews
authors.forename: Miriam
authors.initials: M
authors.lastname: Sturkenboom
authors.forename: Patrick
authors.initials: P
authors.lastname: Zuber
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.forename: Jan
authors.initials: J
authors.lastname: Bonhoeffer
authors.forename: Jim
authors.initials: J
authors.lastname: Buttery
authors.forename: Nigel
authors.initials: N
authors.lastname: Crawford
authors.forename: Genevieve
authors.initials: G
authors.lastname: Deceuninck
authors.forename: Corinne
authors.initials: C
authors.lastname: de Vries
authors.forename: Philippe
authors.initials: P
authors.lastname: De Wals
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Gutierrez-Gimeno
authors.forename: Harald
authors.initials: H
authors.lastname: Heijbel
authors.forename: Hayley
authors.initials: H
authors.lastname: Hughes
authors.forename: Kwan
authors.initials: K
authors.lastname: Hur
authors.forename: Anders
authors.initials: A
authors.lastname: Hviid
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kelman
authors.forename: Tehri
authors.initials: T
authors.lastname: Kilpi
authors.forename: S K
authors.initials: SK
authors.lastname: Chuang
authors.forename: Kristine
authors.initials: K
authors.lastname: Macartney
authors.forename: Melisa
authors.initials: M
authors.lastname: Rett
authors.forename: Vesta Richardson
authors.initials: VR
authors.lastname: Lopez-Callada
authors.forename: Daniel
authors.initials: D
authors.lastname: Salmon
authors.forename: Francisco
authors.initials: F
authors.lastname: Gimenez-Sanchez
authors.forename: Nuria
authors.initials: N
authors.lastname: Sanz
authors.forename: Barbara
authors.initials: B
authors.lastname: Silverman
authors.forename: Jann
authors.initials: J
authors.lastname: Storsaeter
authors.forename: Umapathi
authors.initials: U
authors.lastname: Thirugnanam
authors.forename: Nicoline
authors.initials: N
authors.lastname: van der Maas
authors.forename: Katherine
authors.initials: K
authors.lastname: Yih
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Hector
authors.initials: H
authors.lastname: Izurieta
mesh_terms: D016208:Databases, Factual; D020275:Guillain-Barre Syndrome / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000009:adverse effects* / Q000276:immunology; D007251:Influenza, Human / Q000517:prevention & control*; D007391:International Cooperation; D012306:Risk; D014611:Vaccination / Q000009:adverse effects*
chemical_list: D007252:Influenza Vaccines
keywords: Adjuvant; Adverse events following immunization (AEFI); CPRD; CSF; Clinical Practice Research Datalink; Department of Defense; Department of Veterans Affairs; DoD; GP; Guillain Barré Syndrome (GBS); ICPI; Integrated Primary Care Information Database; International; MCRI; Maccabi; Maccabi Health Maintenance Organization; Monovalent H1N1 Vaccine (H1N1); Murdoch Children's Research Institute; NNI/CGH; NNI/TTSH; National Neuroscience Institute Singapore General Hospital; National Neuroscience Institute Tan Tock Seng Hospital; PRISM; Post-Licensure Rapid Immunization Safety Monitoring; Self-controlled case-series method (SCCS); VA; VAESCO; VSD; Vaccine Adverse Event Surveillance and Communication Consortium; Vaccine Safety Datalink; cerebrospinal fluid; general practitioner