Guillain-Barré syndrome (GBS) is a rare disorder in which a person’s own immune system damages their nerve cells, causing muscle weakness and sometimes paralysis. It often follows infection with a virus or bacteria. Most people recover fully from GBS, but some people have permanent nerve damage. In the United States, about 3,000 to 6,000 people develop GBS each year, whether or not they received a vaccination.
Studies suggest that it is more likely that a person will get GBS after getting the flu than after vaccination. It is important to keep in mind that severe illness and death are associated with flu, and getting vaccinated is the best way to prevent flu infection and its complications.
Vaccine safety monitoring systems are used to investigate cases of GBS that start after vaccination. Tracking vaccine safety is a high priority for the Centers for Disease Control and Prevention. Several systems are in place to monitor vaccine safety.