What causes GBS?
Scientists do not fully understand what causes GBS, but it is believed that stimulation of the body’s immune system may play a role in its development. Here’s what scientists know for sure: About two-thirds of people who develop GBS symptoms do so several days or weeks after they have been sick with a diarrheal or respiratory illness. Infection with the bacterium Campylobacter jejuni is one of the most common risk factors for GBS. People can also develop GBS after having the flu or other infections (such as cytomegalovirus and Epstein Barr virus). On very rare occasions, they may develop GBS in the days or weeks following receiving a vaccination.