Guillain Barré Syndrome is an autoimmune disorder that is present in the body and awakened into activity by a challenge to the immune system. The influenza virus is known to trigger the activation of GBS. Since influenza vaccines also mildly challenge the immune system, about 1 in 1 million people will have an activation of GBS after being vaccinated (however it’s reasonable to believe that if the inactive virus in the vaccine could wake it up, then infection with the live virus would have certainly resulted in activation.) The risk of the vaccine triggering GBS scares a lot of people. Most people do not understand how the influenza vaccine can both protect against GBS while also rarely triggering the thing it’s supposed to prevent.
It may help if we think of Guillain Barré as a sleeping giant then think of influenza infection as a big loud ogre and the influenza vaccine as a tiptoeing fairy. If the giant is awoken by a tiptoeing fairy, then it almost certainly would have been awoken by a loud ogre. We do not know which individuals are harboring the sleeping giant named Guillain Barré. Once inside, if the tiptoeing fairy was successful in not waking the giant (and she almost always is) she casts a spell making the loud ogre (influenza) invisible, silent, and incapable of waking the sleeping giant.
In this way, receiving the influenza vaccine actually reduces the risks of GB activation by the influenza virus in patients who unknowingly harbor this sleeping giant.