Chronic Diseases
Uncovering how Epstein-Barr virus drives MS
Maya Brownstein
July 23, 2026
In a new study, researchers led by Harvard T.H. Chan School of Public Health’s Kjetil Bjornevik uncovered a key mechanism driving the link between Epstein-Barr virus (EBV) and multiple sclerosis (MS)—a finding that could inform the development of new therapies for the chronic autoimmune disease
The study was published July 15 in Science Translational Medicine. Bjornevik, assistant professor of epidemiology and nutrition, was the first author
Previous Harvard Chan School-led research showed that EBV is a trigger for MS, increasing the risk of developing the disease 32-fold. But while EBV is among the most common viruses in the world, MS is rare. More than 95% of adults are infected with EBV—it lays dormant in most—and fewer than 1% develop MS. Bjornevik and colleagues hypothesized that those who do develop the disease have a unique immune response to EBV—one requiring further study
“EBV is now considered a causal factor, not just a common finding. Still, several open questions remain, and they are important to answer if we are able to translate these findings into something that can benefit patients and those at risk,” Bjornevik said in a July 15 Boston Globe article about the study. “The natural next step is to examine the immune response directly.”
To do so, the researchers analyzed blood samples among three groups of study participants: healthy individuals free of MS, those with untreated MS, and those receiving MS therapies. They found that, compared to MS-free participants, those with untreated MS mounted a doubled immune response to EBV, indicated by increased activity among CD4+ T cells—a type of immune cell that triggers inflammation
The study also found that common MS treatments significantly decreased EBV-specific CD4+ T cells and eliminated the presence of EBV in saliva, the virus’ primary mode of transmission
According to the researchers, the findings could guide development of new drugs to treat MS as well as vaccines against EBV
“Our results establish preferential CD4+ T cell reactivity to EBV … as a key feature of MS, providing a framework for developing EBV-targeted therapies, including vaccines and antivirals,” they wrote
Bjornevik echoed this potential in the Boston Globe. “We need to understand the underlying mechanisms [of how EBV can lead to MS],” he said. “Findings like this could motivate companies to develop new treatments,” he said
Read the Boston Globe article:
From ‘kissing disease’ to MS: Harvard study uncovers how a common virus triggers multiple sclerosis
Read about the study in Inside Precision Medicine:
Virus Response Insights Offer MS Treatment Hope
Read about the study in Medical Xpress:
New study sheds light on how Epstein-Barr virus may contribute to multiple sclerosis
Learn more:
Alberto Ascherio receives Breakthrough Prize for groundbreaking research on multiple sclerosis (Harvard Chan School news)
Exploring links between viruses and neurological disorders (Harvard Chan School news)
About The Author
Maya Brownstein
Media Relations Manager in the Office of Communications
Related Topics
Chronic Diseases
Last Updated
Featured in this article
Kjetil Bjornevik
Assistant Professor of Epidemiology and Nutrition
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