Flu Vaccine May Protect Against Guillain-Barré Syndrome

A new simulation study that evaluated the relationship between Guillain-Barré syndrome (GBS) risk and influenza vaccine and illness suggests that the vaccine reduces the risk for GBS. Researchers found that influenza vaccination reduces individual risk for GBS for most patients under typical conditions (vaccine effectiveness >60 percent; influenza incidence rates >5 percent). Results showed a small reduction in absolute risk of GBS with vaccination compared with no vaccination for a hypothetical 45-year-old woman (-0.36/1 million vaccinations; 95% credible interval, -1.22% to 0.28%), as well as for a hypothetical 75-year-old man (-0.42/1 million vaccinations; 95% credible interval, -3.68% to 2.44%). Exceptions to the rule of protection were predicted in conditions of low vaccine effectiveness and/or low influenza incidence. According to the researchers, the efficacy of a vaccine will vary by year and region and is dependent on the antigen match between the circulating virus strains and the vaccine. Previously published studies have separately evaluated the risk that a patient who receives the seasonal influenza vaccine or contracts influenza will be diagnosed with GBS from influenza. The study was published in the Jan. 14 online edition of Emerging Infectious Diseases.