title: Erratum to: Reassessing the risk of natalizumab-associated PML.
authors.affiliation: Multiple Sclerosis Division of the Department of Neurology, University of Pennsylvania, 3400 Spruce St., 3 W Gates, Philadelphia, PA, 19104, USA. joseph.berger@uphs.upenn.edu.|Mellen Center for Multiple Sclerosis Treatment and Research, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA. joseph.berger@uphs.upenn.edu.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Berger
authors.affiliation: Multiple Sclerosis Division of the Department of Neurology, University of Pennsylvania, 3400 Spruce St., 3 W Gates, Philadelphia, PA, 19104, USA.|Mellen Center for Multiple Sclerosis Treatment and Research, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Fox