5-20% of people with MS
A person experiences one or two attacks over the course of the illness but stays largely well. The first attack often affects vision or another sense, but the person remains active. Usually, subtle damage is occurring despite the lack of relapses.
If someone with MS has remained mostly functional for 15 years, they are generally considered to have benign MS. Its numbers are probably overestimated because we don’t connect it to subtle problems like fatigue and cognitive, social, and/or psychological issues.
For more information on all these topics, please see the MS Encyclopedia.