What is the Connection Between Guillain-Barre Syndrome and the Flu Shot?

The connection between Guillain-Barre syndrome and the flu shot stems from the swine flu outbreak that occurred in the United States in 1976. The flu vaccination appeared to increase the risk of developing the syndrome, although the reason why is still unclear. Due to the link between Guillain-Barre syndrome and the flu shot, the vaccine was taken off the market in the U.S. in December of 1976, but the swine flu vaccination used today does not seem to be associated with the disorder. Guillain-Barre syndrome is an autoimmune disorder in which the body’s immune system attacks parts of the nervous system.

During the 10-week period that the swine flu shot was available in the U.S. in 1976, about 48 million Americans received it. Of those, about 500 people were diagnosed with Guillain-Barre syndrome after being vaccinated. The association between Guillain-Barre syndrome and the flu shot was a slight increase in risk of developing the disorder. The risk at that time from getting the shot was about two in 100,000 people, which is slightly higher than the risk of getting the disorder without receiving the flu shot. The vaccination was stopped after just 10 weeks that year because of the relationship between the shot and the disorder combined with the fact that the swine flu was not widespread at the time.

Initial reports after finding the connection between the Guillain-Barre syndrome and the flu shot indicated that the vaccine increased the risk of the disorder by seven or eight times. Those numbers might have been inflated, however, because the reports did not take into account if people had other conditions that could also lead to the disorder. The Institute of Medicine in the U.S. conducted research regarding the connection between Guillain-Barre syndrome and the flu shot, but no specific reason for the link could be found.

The swine flu shot that is available now is different from the one used in the U.S. in 1976. There appears to be no association between Guillain-Barre syndrome and the flu shot currently on the market. The Centers for Disease Control and Prevention (CDC) continuously monitors the safety of the vaccine in the U.S. The risk of developing the disorder after getting a flu shot is approximately less than one or two cases per million people vaccinated, although there is no clear relationship between them.

Since Guillain-Barre syndrome is a disorder that effects the nervous system, it can cause permanent nerve damage, and in rare cases, death. Symptoms include tingling and numbness, muscle weakness in the arms and legs, difficulty breathing, and paralysis. There is no cure for the syndrome, but with treatment, most people recover.