The risk of Guillain-Barré syndrome after influenza vaccination
Guillain-Barre syndrome (GBS) is an immune-mediated flaccid paralysis that can range from muscle weakness and tingling to respiratory paralysis requiring prolonged respiratory support and ventilation. Overall, GBS is a rare disease, with annual incidence averaging 1 to 2 cases per 100,000 individuals.1
The cause of this autoimmune disease is thought to be the result of molecular mimicry between gangliosides (a type of glycolipid found in cell membranes with high concentrations in nervous system tissues) and lipopolysaccharides of bacteria and viruses.1 Essentially, antibodies formed against an antigenic component of a pathogen also have affinity for a component of the host’s cell membrane, such as a glycolipid.
Approximately one-third of all GBS cases are preceded by Campylobacter jejuni infections, a common cause of gastrointestinal illness.1 The risk of GBS is estimated to be over 38 times greater for those who have been recently infected by C. jejunii and over 18 times greater for those with influenza and influenza-like illnesses.2
An increased rate of GBS was observed during the 1976 swine flu vaccination campaign, with approximately one additional case of GBS per 100,000 individuals vaccinated above background rates (532 cases in 45 million vaccinees).3