• Posted April 15, 2026

An Infectious Combo Triples Risk Of MS, Study Says

An Epstein-Barr virus infection that results in a case of mono appears to triple the risk of one day developing multiple sclerosis, a new study says.

Epstein-Barr, a herpes virus, is the most common cause of infectious mononucleosis, researchers said.

Now, it seems that one-two punch might increase the risk of the degenerative brain disease MS, according to findings recently published in Neurology Open Access.

“These results highlight the need for further research into ways to prevent infection with the Epstein-Barr virus,” said lead researcher Jennifer St. Sauver, an epidemiologist at the Mayo Clinic in Rochester, Minnesota.

“Preventing these infections could reduce the overall burden of MS,” St. Sauver said in a news release. “While MS is relatively rare, it carries the risks of significant disability and high treatment costs, and it usually develops when people are in their prime years of working and raising families.”

For the study, researchers analyzed more than two decades of health care records to find people who had a positive test for Epstein-Barr virus and infectious mononucleosis, identifying 4,721 patients.

The team compared each person with three other people the same age and sex who never had mono, to see if there were any differences in rates of MS.

During an average eight years of follow-up, eight people who’d had mono developed MS, or about 0.17%.

By comparison, 10 people who never had mono developed MS, but their larger group meant that they represented only 0.07%.

All told, people who’d had mono were a little more than three times as likely to develop MS, results show.

“Mononucleosis is a relatively uncommon illness, but developing strategies to prevent infection with the virus that causes this disease could help us to lower the number of MS cases in the future,” St. Sauver said.

These results are in line with other studies that have linked Epstein-Barr virus or mononucleosis to MS, researchers said.

Researchers could not say why mono caused by Epstein-Barr might raise MS risk.

They also noted that their study doesn’t prove a cause-and-effect link between mono and MS, but only shows an association.

More information

The U.S. Centers for Disease Control and Prevention has more about mononucleosis.

SOURCE: American Academy of Neurology, news release, April 1, 2026