Guillain-Barré Syndrome Following Influenza Vaccination

International collaboration to assess the risk of Guillain Barré Syndrome following Influenza A (H1N1) 2009 monovalent vaccines

“…Because GBS following vaccination is very rare with reported rates between 0.04 and 0.17 cases per 100,000 vaccinations [22], this combined analysis included a much larger number of cases than any published single country analysis and allowed inclusion of data from sites that did not have enough cases for a site-specific analysis. This provided both increased power to evaluate the outcome but also sufficient power to conduct sub-analyses by vaccine type.…”

Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination

“…Further, the event should occur within a defined window of risk following vaccine administration and for many AEFIs this defined risk window is not established. The CCCR working group assigned a risk interval for onset of GBS symptoms, and all demyelinating disorders, of 8 weeks following receipt of vaccine based on the available evidence [9,18]. Also, the pathophysiologic mechanism by which the vaccine causes disease must make biological sense.…”

“…For a causal assessment of "possible" using these modified criteria, known causes that were more likely associated with the event needed to have been excluded. Therefore, if an upper respiratory or gastrointestinal illness was reported in the 4 weeks preceding GBS symptom onset, both associated with GBS in the literature [16], the case would not be causally assessed as "possibly" related to vaccine (and therefore would be classified as either "unlikely" or "unrelated") since the preceding illness represented a "more likely" cause of the adverse event [17][18] (Figure 1). In reports with laboratory evidence of a co-existent infection, the working group did not assess these cases as causally "unrelated" to vaccine, but rather "unlikely", since it was not certain that the co-existent infection caused the adverse event.…”

Guillain-Barre syndrome associated with peginterferon alfa-2a for chronic hepatitis C: A case report

“…CSF pleocytosis is common in patients who have GBS and concurrent HIV infection [13] but our patient had only 3 WBCs. Certain vaccinations such as Influenza vaccination [14] and Meningococcal vaccination have also been associated with GBS but our patient did not receive any of these vaccines. Industrial toxins and drugs can also cause demyelinating neuropathies.…”