Check out ehealthline.com for more info on Tysabri and PML incidents.
A rather newish site with great info.
On Jan, 2, 2014: 90,291 people reported to have side effects when taking
Tysabri. Among them, 2,583 people (2.86%) have Progressive Multifocal
Leukoencephalopathy. Higher than reported by Biogen.
http://www.ehealthme.com/ds/tysabri/...encephalopathy
Also...
https://www.facebook.com/notes/ccsvi...51730298782211