My mom had GBS, or has it's in remission. Struck her in 88. It was due to trauma from an accident. GBS has been around for a long time and at them time she had it she was still an unvaccinated adult and GBS was considered an orphan disease.
Wanted to add that in the 70's there was an outbreak of GBS due to the Flu vaccine. However that is not the only way one could suffer from GBS.