Risk of Guillain-Barre syndrome following pandemic influenza A (H1N1) 2009 vaccination in Germany

PurposeA 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-Barre syndrome (GBS) and its variant Fisher syndrome (FS). MethodsPotential 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. ResultsOut of 676 GBS/FS reports, in 30 cases, GBS/FS (BC levels 1-3) occurred within 150days 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 3weeks 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. ConclusionsThe results indicate an increased risk of GBS/FS in temporal association with pandemic influenza A(H1N1) vaccination in Germany. (c) 2014 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons, Ltd.