The general cause of Guillain-Barre syndrome stems from a miscommunicated response by the immune system that prompts an attack on parts of the nervous system, usually in reaction to the presence of foreign agents. These substances include the influenza virus, which can elicit an immune system reaction. Studies have observed a possible link between Guillain-Barre syndrome and vaccination, specifically in the potentially higher incidence of the disorder in individuals who were given influenza vaccines.
The Guillain-Barre syndrome is significant in its designation as an autoimmune nerve disorder because of the severe, sometimes fatal, symptoms that affected patients may endure. The possible connection Guillain-Barre syndrome and vaccination was first brought to light in 1976 during a national campaign for swine flu vaccination, when 25 people died because of complications from Guillain-Barre.
An investigation was initiated that revealed a higher incidence of Guillain-Barre syndrome in recipients of the flu shot than non-recipients — one additional case of Guillan-Barre per 100,000 shots or 10 per million. The results from these earlier investigations, which appeared to have uncovered a link between Guillain-Barre syndrome and vaccination, remain uncertain, however. It had also been theorized that the influenza vaccine may not have been the direct cause in these cases, but rather, a consequence of contamination in the vaccine supply.
Guillain-Barre syndrome has not had a statistically clear association with any other influenza vaccines since the swine flu cases in 1976, and the majority of studies have found no causal relation between Guillain-Barre syndrome and vaccination. Only two studies since have reported a slight risk of higher incidence of Guillain-Barre syndrome in those who receive the seasonal flu vaccination — around one additional case per 1,000,000 vaccinations. Overall, the connection between Guillain-Barre syndrome and vaccination of the seasonal flu has been inconsistent. The rarity of this disorder in all populations, estimated to be one or two cases per 100,000, complicates efforts to determine whether its occurrence in vaccinated individuals can be considered a definitive vaccination side effect.
Studies continue as scientists examine the uncertain connection between Guillain-Barre syndrome and vaccination, and vaccine safety and reporting systems have been created to track and identify cases of Guillain-Barre syndrome that appear in individuals after receiving the influenza vaccine. While a slightly higher incidence rate of Guillain-Barre syndrome has been observed with the swine flu vaccine, the possibility of developing serious complications from contracting influenza is a much more significant risk. An estimated 30,000 deaths occur each year because of complications from influenza, and vaccination is recommended as the best safeguard.