Regionally, the median estimated prevalence of MS is greatest in Europe (80 per 100,000), followed by the Eastern Mediterranean (14.9%), the Americas (8.3%), the Western Pacific (5%), South-East Asia (2.8%) and Africa (0.3%). Regionally, the median estimated incidence of MS is greatest in Europe (3.8 per 100 000), followed by the Eastern Mediterranean (2%), the Americas (1.5) and the Western Pacific.
Multiple Sclerosis is classified into 4 forms:
- Relapsing-Remitting MS (RRMS): the most common form of multiple sclerosis (75-85%). It is a cyclic form characterized by relapses with stable neurologic disability between episodes.
- Secondary-Progressive MS (SPMS): The majority of patients after an initial remitting phase evolve within a variable period of 5 to 20 years through a secondary progressive form.
- Primary-Progressive MS (PPMS). This type of MS is not very common, occurring in about 10% of MS patients, more frequent for patients after 40 years of age. PPMS is a progressive course from disease onset characterized by slowly worsening symptoms from the beginning, with no relapses or remissions.
- Progressive-Relapsing MS (PRMS). A rare form of MS (5%), PRMS is characterized by a steadily worsening disease state from the beginning, with acute relapses but no remissions, with or without recovery.