Simulation Study of the Effect of Influenza and Influenza Vaccination on Risk of Acquiring Guillain-Barré Syndrome

Steven Hawken,Natasha S Crowcroft,Robin Ducharme,Michael A Campitelli,Jeffrey C Kwong,Kumanan Wilson,Allison J Mcgeer,Doug Coyle,Shelley L Deeks

doi:10.3201/eid2102.131879

Abstract

It is unclear whether seasonal influenza vaccination results in a net increase or decrease in the risk for Guillain-Barré syndrome (GBS). To assess the effect of seasonal influenza vaccination on the absolute risk of acquiring GBS, we used simulation models and published estimates of age- and sex-specific risks for GBS, influenza incidence, and vaccine effectiveness. For a hypothetical 45-year-old woman and 75-year-old man, excess GBS risk for influenza vaccination versus no vaccination was -0.36/1 million vaccinations (95% credible interval -1.22% to 0.28) and -0.42/1 million vaccinations (95% credible interval, -3.68 to 2.44), respectively. These numbers represent a small absolute reduction in GBS risk with vaccination. Under typical conditions (e.g. influenza incidence rates >5% and vaccine effectiveness >60%), vaccination reduced GBS risk. These findings should strengthen confidence in the safety of influenza vaccine and allow health professionals to better put GBS risk in context when discussing influenza vaccination with patients.

Highlights

Seasonal influenza vaccination programs have been implemented in many jurisdictions over the past 40 years
Base-Case Analyses When a 45-year-old woman was used as the base case, excess Guillain-Barré syndrome (GBS) risk for influenza vaccination versus no vaccination was calculated to be –0.36/1 million vaccinations (95% credible interval (CrI) –1.22 to 0.28), representing a small absolute reduction in GBS risk
When a 75-year-old man was used as the base case, the excess GBS risk due to vaccination was estimated to be –0.42/1 million vaccinations (95% CrI –3.68 to 2.44), and 65% of simulated absolute risk differences were

Summary

Introduction

Seasonal influenza vaccination programs have been implemented in many jurisdictions over the past 40 years. Previous studies estimate that influenza illness may increase the risk for GBS by up to 16- to 18fold, whereas influenza vaccination may only increase the risk by up to 2-fold [4,5,6,7,8,9,10,11,12,13,14] (online Technical Appendix Table 1, http://wwwnc.cdc.gov/EID/article/21/2/13-1879Techapp1.pdf) On balance, it is unclear whether vaccination against seasonal influenza results in a net increase or decrease in the absolute risk of a person acquiring GBS. The objective of this study was to assess, by using a simulation modeling approach, the effect of receipt of a seasonal influenza vaccine on a person’s age- and sex-specific absolute risk of acquiring GBS

Objectives

Methods

Results

Conclusion