That would depend on if its genuine EC, or if its been misdiagnosed, to be honest, and so much is misdiagnosed.
As far as I know, genuine EC can not be fully recovered from because of the nature of what it does to the body, so one might suspect that if the bunny is healthy and has remained healthy, that it was misdiagnosed.
If a bunny has genuine EC then it has an 'issue' (normally the first sign is a weak back left leg), and it recovers as the immune system fights it, then, as the spore takes hold again, it has another issue, and then the immune system mounts a greater fight so the symptom can ease, and then it carries on like that until the immune system can no longer fight anymore and the bunny loses its battle.
Please note, this is what I have learnt, researched and been told and is my opinion only. My opinion tends to differ from the masses. :lol:
I had a bunny with head tilt who had an inner ear infection and she lived another 15 months and then died of secondary uterine cancer and no remaining infection issues.