Risk of Guillain-Barré syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study

The Lancet Infectious Diseases
Sep 2013  Volume 13  Number 9   p725 – 822
http://www.thelancet.com/journals/laninf/issue/current

Comment –
Association between vaccination and Guillain-Barré syndrome

Lucija Tomljenovic, Yehuda Shoenfeld
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Guillain-Barré syndrome is a serious neurological autoimmune disorder characterised by inflammatory demyelination of peripheral nerves.1 Up to 25% of patients experience respiratory failure,2 and 4% die within the first year from disease complications.3 The disorder can be triggered by viral infections and bacterial and viral vaccinations.1,4 After the 1976 influenza vaccine campaign in the USA, an increase in the rate of Guillain-Barré syndrome resulted in the suspension of the vaccination programme…

Risk of Guillain-Barré syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study
Dr Jeffrey C Kwong MD a b c j k, Priya P Vasa MD b l, Michael A Campitelli MPH a, Steven Hawken MSc a, Kumanan Wilson MD a g h, Laura C Rosella PhD a c j, Prof Therese A Stukel PhD a d, Natasha S Crowcroft MD(Cantab) c e j, Prof Allison J McGeer MD c e, Lorne Zinman MD f i, Shelley L Deeks MD c j

http://www.thelancet.com/journals/laninf/article/PIIS1473-3099%2813%2970104-X/abstract

Summary

Background

The possible risk of Guillain-Barré syndrome from influenza vaccines remains a potential obstacle to achieving high vaccination coverage. However, influenza infection might also be associated with Guillain-Barré syndrome. We aimed to assess the risk of Guillain-Barré syndrome after seasonal influenza vaccination and after influenza-coded health-care encounters.

Methods

We used the self-controlled risk interval design and linked universal health-care system databases from Ontario, Canada, with data obtained between 1993 and 2011. We used physician billing claims for influenza vaccination and influenza-coded health-care encounters to ascertain exposures. Using fixed-effects conditional Poisson regression, we estimated the relative incidence of hospitalisation for primary-coded Guillain-Barré syndrome during the risk interval compared with the control interval.

Findings

We identified 2831 incident admissions for Guillain-Barré syndrome; 330 received an influenza vaccine and 109 had an influenza-coded health-care encounter within 42 weeks before hospitalisation. The risk of Guillain-Barré syndrome within 6 weeks of vaccination was 52% higher than in the control interval of 9—42 weeks (relative incidence 1·52; 95% CI 1·17—1·99), with the greatest risk during weeks 2—4 after vaccination. The risk of Guillain-Barré syndrome within 6 weeks of an influenza-coded health-care encounter was greater than for vaccination (15·81; 10·28—24·32). The attributable risks were 1·03 Guillain-Barré syndrome admissions per million vaccinations, compared with 17·2 Guillain-Barré syndrome admissions per million influenza-coded health-care encounters.

Interpretation

The relative and attributable risks of Guillain-Barré syndrome after seasonal influenza vaccination are lower than those after influenza illness. Patients considering immunisation should be fully informed of the risks of Guillain-Barré syndrome from both influenza vaccines and influenza illness.

Funding

Canadian Institutes of Health Research.