Table 2

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

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

Author affiliations: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (S. Hawken, J.C. Kwong, R. Ducharme, M.A. Campitelli, K. Wilson); Ottawa Hospital Research Institute, Ottawa, Ontario, Canada (S. Hawken, R. Ducharme, K. Wilson); University of Ottawa, Ottawa (S. Hawken, D. Coyle, K. Wilson); Public Health Ontario, Toronto (J.C. Kwong, S.L. Deeks, N.S. Crowcroft); Dalla Lana School of Public Health, University of Toronto, Toronto (J.C. Kwong, S.L. Deeks, N.S. Crowcroft, A.J. McGeer); University of Toronto, Toronto (J.C. Kwong, N.S. Crowcroft, A.J. McGeer)

Main Article

Excess risk for GBS per million influenza vaccinations overall and for males and females separately by various influenza incidence rates in a simulated study*

Age, y, sex	∆GBS risk (95% CrI), % ΔGBS risk <0, by influenza incidence rate†
Age, y, sex	2%	5%	10%	15%	20%
45
Both	0.49 (−0.03 to 1.35), 3.5⁽⁺⁾	0.12 (−0.55 to 0.93), 35.7^(±)	−0.48 (−1.63 to 0.37), 87.1⁽⁻⁾	−1.08 (−2.79 to −0.07), 98.2⁽⁻⁾	−1.69 (−3.99 to −0.43), 99.7⁽⁻⁾
F	0.37 (−0.02 to 1.01), 3.5⁽⁺⁾	0.09 (−0.41 to 0.70), 35.6^(±)	−0.36 (−1.22 to 0.28),‡ 87.0⁽⁻⁾	−0.82 (−2.09 to −0.05), 98.2⁽⁻⁾	−1.28 (−2.98 to −0.33), 99.7⁽⁻⁾
M	0.66 (−0.05 to 1.79), 3.5⁽⁺⁾	0.16 (−0.74 to 1.24), 35.6^(±)	−0.65 (−2.16 to 0.50), 87.1⁽⁻⁾	−1.46 (−3.69 to −0.09), 98.1⁽⁻⁾	−2.28 (−5.27 to −0.59), 99.7⁽⁻⁾
75
Both	0.90 (0.19 to 2.71), 2.2⁽⁺⁾	0.43 (−0.79 to 2.20), 22.6⁽⁺⁾	−0.31 (−2.58 to 1.74), 64.7^(±)	−1.07 (−4.55 to 1.51), 82.6⁽⁻⁾	−1.84 (−6.60 to 1.38), 89.3⁽⁻⁾
F	0.69 (0.02 to 2.18), 2.3⁽⁺⁾	0.32 (−0.61 to 1.77), 22.6⁽⁺⁾	−0.23 (−2.06 to 1.37), 64.7^(±)	−0.80 (−3.67 to 1.16), 82.5⁽⁻⁾	−1.39 (−5.33 to 1.05), 89.3⁽⁻⁾
M	1.23 (0.02 to 3.90), 2.3⁽⁺⁾	0.58 (−1.09 to 3.15), 22.6⁽⁺⁾	−0.42 (−3.68 to 2.44),‡ 64.8^(±)	−1.44 (−6.54 to 2.09), 82.6⁽⁻⁾	−2.48 (−9.47 to 1.89), 89.2⁽⁻⁾

*Assuming vaccine effectiveness of 61% for 45-year-old persons and 50% for 75-year-old persons. Assuming semi-additive effect whereby those vaccinated and who experience influenza illness experience the sum of the 2 relative risks (RR) (i.e., influenza illness RR = 15.81 + 1.52 = 17.33). A total of 1,000,000 simulations were conducted for each scenario. GBS, Guillain-Barré syndrome. Explanations for superscript symbols: (+) <25% of estimates have ∆GBS <0 (favors vaccination increasing GBS risk); (±) 25%–75% of estimates have ∆GBS <0 (neutral); (−) >75% of estimates have ∆GBS <0 (favors vaccination decreasing GBS risk).
†Absolute risk difference between vaccinated and unvaccinated persons. Negative values for ∆ GBS indicate net reduction in no. of GBS cases in vaccinated vs. unvaccinated persons. The % of ∆GBS <0 is the percentage of simulation results where the absolute risk difference for vaccinated vs. unvaccinated was <0 (i.e., protective).
‡Base-case analyses.

Main Article

Page created: January 20, 2015

Page updated: January 20, 2015

Page reviewed: January 20, 2015

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