• A new study of more than 10 million people found that the risk of developing multiple sclerosis (MS) rose by 32 times following infection with the Epstein-Barr virus (EBV).
• Researchers could not find any other explanation for MS development in these individuals, noting that EBV could therefore be “the leading cause of MS.”
• The study authors suggest that targeting EBV in the future could be key to finding a cure for MS.

Scientists have long suspected that a link exists between the Epstein-Barr virus and the development of multiple sclerosis. Researchers behind a new study believe they have found the most definitive evidence so far that identifies EBV as the main trigger of MS.

Researchers from the Harvard T.H. Chan School of Public Health analyzed data from more than 10 million members of the U.S. military for the study, published Jan. 13 in the journal Science. They reviewed participants’ medical records over 20 years to evaluate whether a link existed between EBV and MS, and found a 32-fold higher MS risk following infection with EBV. The study authors were not able to identify any other explanation for MS development among study participants, suggesting Epstein-Barr as “the leading cause of MS,” they wrote.

EBV can cause mononoculosis — a common disease among teenagers — and no vaccine currently exists to prevent infection with Epstein-Barr. However, researchers believe that finding a way to curb EBV infection could be the key to eliminating MS.

“The extremely low MS risk in EBV-negative individuals suggests that by far most MS cases are caused by EBV and could thus potentially be prevented by a suitable vaccine,” the study authors wrote.

It’s important to note that not everyone with EBV will go on to develop MS. In fact, about 95 percent of people in the world are infected with Epstein-Barr at some point in their lives. But fewer than 3 million people worldwide have MS, which means multiple sclerosis affects less than 0.04 percent of the world’s population. Since the majority of study participants who developed MS had also been infected with EBV, the study authors believe their findings should bolster current research into preventing EBV spread in future populations.

“This is a big step because it suggests that most MS cases could be prevented by stopping EBV infection, and that targeting EBV could lead to the discovery of a cure for MS,” said senior author Dr. Alberto Ascherio in a statement about the study.

“Currently there is no way to effectively prevent or treat EBV infection, but an EBV vaccine or targeting the virus with EBV-specific antiviral drugs could ultimately prevent or cure MS,” Dr. Ascherio said.