 Later,

Some reports state that those "types" were artificially made up trying to classify RRMS as a separate disease so that the number of patients was low enough to get the interferon approved by the FDA under the orphan drugs act.Revisions in 2013 and 2017 removed the Progressive-Relapsing course and introduced CIS as a variety/course/status of MS, establishing the actual classification (CIS, RRMS, SPMS and PPMS).Nevertheless, these types are not enough to predict the responses to medications and several regulatory agencies use additional types in their recommendations lide Highly active MS, Malignant MS, Aggressive MS or Rapidly progressive MS.

As of 2019, HAMS is defined as an RRMS phenotype with one or more of the following characteristics