I figured it like this:
Chances of MS? Roughly 1 in 75,000 (in Canada). (*That's a very rough estimate).
I have MS.
Chances of PML from Tysabri? 1 in 1,000.
For having a disease for approximately 8 years now (going by my neurologist's best guess) and having sensory symptoms only.. Tysabri for me is not worth the risk, what so ever.
I'd go back to site reactions, muscle spasms, bed wetting and horrific nightmares on Copaxone before Tysabri ever crossed my radar.