>>40
Individuals in the same self-selection surveys did report that for some of them it made their symptoms worse, but they were in the minority. From what I was reading the hypothesis as to why it might help is related to a cause of CFS where a virus persists in the body, and your immune system continues to react to it causing inflamation etc. but without being able to completely purge the body of it. I did get my vaccine and my symptoms did improve, but it's not clear if this was the primary factor to me, and it seems as >>38 says, there really isn't sound science on the topic yet.