Mono Infection Linked to Higher Risk of Multiple Sclerosis

New study finds people with a history of mononucleosis are over three times more likely to develop MS.

Apr. 3, 2026 at 4:10pm

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A ghostly, translucent X-ray-style image showing the internal structures of a human brain, with glowing neural pathways and subtle hints of inflammation, conceptually representing the link between viral infection and autoimmune conditions like multiple sclerosis.An X-ray-like image reveals the intricate neural structures of the brain, hinting at the complex relationship between viral infection and autoimmune disease.Rochester Today

A study from the Mayo Clinic has found that people who have had mononucleosis, also known as mono, caused by the Epstein-Barr virus (EBV) are over three times more likely to later develop multiple sclerosis (MS) compared to those who have not had mono. The researchers analyzed medical records of over 4,700 people with confirmed EBV-related mono and compared them to a larger group without mono, finding the mono group had a significantly higher risk of MS even after accounting for other factors.

Why it matters

The findings add to growing evidence that EBV, a common virus that infects most people, may be a leading cause of MS, a debilitating autoimmune disease. However, the vast majority of people infected with EBV do not go on to develop MS, so more research is needed to understand the complex triggers behind the condition.

The details

The study examined the medical records of 4,721 people diagnosed with mono linked to a positive EBV test, comparing them to 14,163 people without a mono history. Over a median follow-up period of 6-8 years, the researchers found that people with a past mono infection were over 3 times more likely to later develop MS, even after adjusting for other factors like smoking and depression history.

  • The study was published on April 3, 2026.

The players

Mayo Clinic

A nonprofit organization committed to clinical practice, education and research, operating major campuses in Rochester, Minnesota and other locations.

Epstein-Barr Virus (EBV)

A type of herpesvirus that infects most people worldwide and can cause the illness known as mononucleosis or "mono".

Multiple Sclerosis (MS)

A chronic, often disabling autoimmune disease that affects the central nervous system, causing a range of symptoms like muscle weakness, vision problems, and cognitive impairment.

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What’s next

The study authors say the findings highlight the urgent need to develop effective vaccines that can prevent EBV infection, or at least the type of EBV infection that may lead to MS.

The takeaway

This study provides further evidence of a link between the common Epstein-Barr virus and the development of multiple sclerosis, underscoring the importance of continued research to understand the complex triggers behind this debilitating autoimmune condition.