Health

Stronger evidence linking Epstein-Barr virus to multiple sclerosis: study

There is more evidence that one of the world’s most common viruses may set some people on the path to developing multiple sclerosis.

Multiple sclerosis is a potentially disabling disease that occurs when cells of the immune system mistakenly attack the protective layer on nerve fibres, gradually eroding it.

It has long been suspected that the Epstein-Barr virus plays a role in the development of MS. It’s an association that’s hard to prove because nearly everyone develops Epstein-Barr, usually when they are children or young adults — but only a small portion develops MS.

On Thursday, Harvard researchers announced one of the largest studies supporting Epstein-Barr’s theory.

They tracked stored blood samples from more than 10 million people in the US military and found that the risk of developing MS increased 32-fold after Epstein-Barr infection.

The military regularly administers blood tests to its members and researchers examined samples stored from 1993 to 2013, looking for antibodies that indicate a viral infection.

Only 5.3% of recruits showed no sign of Epstein-Barr when they joined the military. Researchers compared 801 subsequently diagnosed MS cases over a 20-year period with 1,566 service members who did not have MS.

Only one MS patient had no evidence of Epstein-Barr virus before diagnosis. And despite extensive research, researchers found no evidence that other viral infections played a role.

The findings “strongly suggest” that Epstein-Barr infection is “a cause rather than a consequence of MS,” study author Dr. Alberto Acchirio of the Harvard T.H. Chan School of Public Health and colleagues report in the Journal of Science.

That’s clearly not the only factor, given that about 90% of adults have antibodies that show they have Epstein-Barr — while nearly 1 million people in the United States live with MS, according to the National Multiple Sclerosis Association.

The virus appears to be the “initial trigger,” Dr. William H. wrote. Robinson and Lawrence Steinman of Stanford University in an editorial accompanying Thursday’s study. But they cautioned that “additional wicks” such as genes that could make people more vulnerable “must be ignited.”

Epstein-Barr is best known for causing “infectious” or “infectious” mononucleosis in adolescents and young adults, but it often occurs without symptoms. It is a virus that remains dormant in the body after initial infection, and it has also been linked to the subsequent development of some autoimmune diseases and rare types of cancer.

It is not clear why. One possibility is so-called “molecular mimicry,” which means that viral proteins may look so similar to some nervous system proteins that they trigger the faulty immune attack.

Regardless, the new study is “the strongest evidence to date that Epstein-Barr contributes to the pathogenesis of multiple sclerosis,” said Mark Allegreta, vice president of research at the National Multiple Sclerosis Society.

This, he added, “opens the door to the potential prevention of MS by preventing Epstein-Barr infection.”

Attempts are underway to develop Epstein-Barr vaccines, including a small study initiated by Moderna Inc. known for its COVID-19 vaccine.

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The Associated Press’s Department of Health and Science receives support from the Howard Hughes Medical Institute’s Division of Science Education. AP is solely responsible for all content.

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