CDC: No clear GBS link to H1N1 Vaccine because WE SAY SO

The following was in the news today and makes me wonder exactly what has to happen before the CDC would consider a case of GBS related to the vaccine?
Va. teen suffers rare illness after swine flu shot; Boy diagnosed with Guillain-Barre syndrome, but CDC says no clear link
In the article they state:

Increased cases of GBS [...]