I apologise for my tardy response; your message went to my SPAM box. The GBS/CIDP Foundation International states that most vaccinations, including COVID and influenza, are safe in individuals who have had GBS with the following exceptions:
1. In the first 12 months following GBS no matter what the triggering event was.
2. If the original GBS attack occurred within 6 weeks of receiving any vaccine, that particular vaccine should be avoided. Thus, if your original GBS occurred within 6 weeks of receiving a COVID vaccination your should avoid that particular vaccine in the future. I am not certain from reading your message exactly when your GBS occurred in relation to the 4th COVID vaccine but if it was more than 6 weeks it is extremely unlikely that the vaccine was the trigger.
I cannot give advice regarding the treatment of individual patients but in general, the benefit of vaccines far outweights any risk. It is essential that you discuss these issues with your doctor before making a decision.