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How Many People Live with MS?


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Nearly 1 million people are living with MS in the United States, according to a study funded by the National MS Society. This is more than twice the original estimate and means solutions for MS are now twice as important. 

Bar graph of MS prevalence estimate, pre-study estimate 300,000-400,000 people living with MS and 2017 estimate is 851,749-913,925. Bar graph of MS prevalence increase over 5 decades (per 100,000 U.S. residents): 58 in 1976; 85 in 1994; 210 in 2009; 309 in 2010; 362 in 2017.

Incidence v. prevalence

Prevalence = the number of people living with a diagnosis of MS at a particular point in time, in a particular place.

Incidence = the number of people NEWLY diagnosed with MS within a given period of time.

The National MS Society funded an important prevalence study that provided a scientifically sound estimate of the number of people over the age of 18 living with MS in the U.S.

MS incidence and prevalence are not consistently reported or tracked in the U.S., and there is no government requirement to do so. In the absence of government-reported data, the National MS Society relies on scientifically-sound estimates of prevalence while we advocate for better and more systematic reporting and tracking at a nationwide level.  

The Centers for Disease Control (CDC) received federal funding to implement a neurological disease surveillance system and will be able to update prevalence estimates on a regular basis. The National MS Society is working with the CDC to help with the development of the surveillance system — a culmination of more than a decade of work by MS activists and others across the neurologic community.

This system will provide important demographic data to help researchers move more quickly toward cures for the millions of people who live with diseases like MS and Parkinson’s Disease.

Landmark study estimates new prevalence number

A study by leading experts estimates that nearly 1 million adults (up to 913,925) are living with MS in the United States. This is more than twice the previously reported number from a national study in 1975 and subsequent updates.

In addition to the main paper outlining these results, two companion papers providing background information on prevalence in the U.S. and reviewing the study methods were also published in the February 15, 2019, online issue of Neurology®, the medical journal of the American Academy of Neurology.

This breakthrough is a pivotal moment in the MS movement as a scientifically sound measure of prevalence helps us better understand the disease and its impact.

Are more people getting MS than ever before?

We don’t know. Since solid information on the number of people being diagnosed with MS has not been available, it has been difficult to tell whether more people are getting MS or if the total number is just a reflection of overall population growth, better diagnostic capabilities the availability of disease modifying drugs, or other changes in the MS landscape. Going forward, this should become easier. Outside of the U.S., some studies have reported increases in the incidence of MS. More work is needed to understand all the factors that led to this increase.


© 2023 The National Multiple Sclerosis Society is a tax exempt 501(c)3 nonprofit organization. Its Identification Number (EIN) is 13-5661935.