tetano
Editor, Senior Moderator
Lancet Infect Dis. 2013 Jun 27. pii: S1473-3099(13)70104-X. doi: 10.1016/S1473-3099(13)70104-X. [Epub ahead of print]
Risk of Guillain-Barr? syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study.
Kwong JC, Vasa PP, Campitelli MA, Hawken S, Wilson K, Rosella LC, Stukel TA, Crowcroft NS, McGeer AJ, Zinman L, Deeks SL.
Source
Institute for Clinical Evaluative Sciences, Toronto, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Canada; Public Health Ontario, Toronto, Canada; University Health Network, Toronto, Canada. Electronic address: jeff.kwong@utoronto.ca.
Abstract
BACKGROUND:
The possible risk of Guillain-Barr? syndrome from influenza vaccines remains a potential obstacle to achieving high vaccination coverage. However, influenza infection might also be associated with Guillain-Barr? syndrome. We aimed to assess the risk of Guillain-Barr? 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-Barr? syndrome during the risk interval compared with the control interval.
FINDINGS:
We identified 2831 incident admissions for Guillain-Barr? syndrome; 330 received an influenza vaccine and 109 had an influenza-coded health-care encounter within 42 weeks before hospitalisation. The risk of Guillain-Barr? 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-Barr? 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-Barr? syndrome admissions per million vaccinations, compared with 17?2 Guillain-Barr? syndrome admissions per million influenza-coded health-care encounters.
INTERPRETATION:
The relative and attributable risks of Guillain-Barr? syndrome after seasonal influenza vaccination are lower than those after influenza illness. Patients considering immunisation should be fully informed of the risks of Guillain-Barr? syndrome from both influenza vaccines and influenza illness.
FUNDING:
Canadian Institutes of Health Research.
Copyright ? 2013 Elsevier Ltd. All rights reserved.
PMID:
23810252
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23810252
Risk of Guillain-Barr? syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study.
Kwong JC, Vasa PP, Campitelli MA, Hawken S, Wilson K, Rosella LC, Stukel TA, Crowcroft NS, McGeer AJ, Zinman L, Deeks SL.
Source
Institute for Clinical Evaluative Sciences, Toronto, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Canada; Public Health Ontario, Toronto, Canada; University Health Network, Toronto, Canada. Electronic address: jeff.kwong@utoronto.ca.
Abstract
BACKGROUND:
The possible risk of Guillain-Barr? syndrome from influenza vaccines remains a potential obstacle to achieving high vaccination coverage. However, influenza infection might also be associated with Guillain-Barr? syndrome. We aimed to assess the risk of Guillain-Barr? 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-Barr? syndrome during the risk interval compared with the control interval.
FINDINGS:
We identified 2831 incident admissions for Guillain-Barr? syndrome; 330 received an influenza vaccine and 109 had an influenza-coded health-care encounter within 42 weeks before hospitalisation. The risk of Guillain-Barr? 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-Barr? 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-Barr? syndrome admissions per million vaccinations, compared with 17?2 Guillain-Barr? syndrome admissions per million influenza-coded health-care encounters.
INTERPRETATION:
The relative and attributable risks of Guillain-Barr? syndrome after seasonal influenza vaccination are lower than those after influenza illness. Patients considering immunisation should be fully informed of the risks of Guillain-Barr? syndrome from both influenza vaccines and influenza illness.
FUNDING:
Canadian Institutes of Health Research.
Copyright ? 2013 Elsevier Ltd. All rights reserved.
PMID:
23810252
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23810252