New findings 'strongly suggest' Epstein-Barr virus may help trigger multiple sclerosis

New findings ‘strongly suggest’ Epstein-Barr virus may help trigger multiple sclerosis

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There’s new evidence that one of the world’s most common viruses may set some people on the path to developing multiple sclerosis (MS).

The potentially disabling disease occurs when immune system cells mistakenly attack the protective coating on nerve fibres, gradually eroding them.

The Epstein-Barr virus, a widespread human herpes virus, has long been suspected of playing a role in development of MS. It’s a connection that’s hard to prove because just about everybody gets infected with Epstein-Barr, usually as kids or young adults — but only a tiny fraction develop MS.

On Thursday, Harvard University researchers reported one of the largest studies yet to back the Epstein-Barr theory.

They tracked blood samples stored from more than 10 million people in the U.S. military and found the risk of MS increased 32-fold following Epstein-Barr infection.

The military regularly administers blood tests to its members and the researchers checked samples stored from 1993 to 2013, hunting antibodies signaling viral infection.

Just 5.3 per cent of recruits showed no sign of Epstein-Barr when they joined the military. The researchers compared 801 MS cases subsequently diagnosed over the 20-year period with 1,566 service members who never got MS.

Only one of the MS patients had no evidence of the Epstein-Barr virus prior to diagnosis. And despite intensive searching, the researchers found no evidence that other viral infections played a role.

The findings “strongly suggest” that Epstein-Barr infection is “a cause and not a consequence of MS,” study author Dr. Alberto Ascherio of the Harvard T.H. Chan School of Public Health and colleagues reported in the journal Science.

Virus best known for causing ‘mono’

It’s clearly not the only factor, considering that about 90 per cent of adults have antibodies showing they’ve had Epstein-Barr — while nearly one million people in the U.S. are living with MS, according to the National Multiple Sclerosis Society.

Canada, meanwhile, has one of the highest rates of MS in the world. Figures from the MS Society of Canada suggest an estimated 90,000 Canadians are living with the disease, or one in every 400 people.

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

Epstein-Barr is best known for causing “mono,” or infectious mononucleosis, in teens and young adults but often occurs with no symptoms. A virus that remains inactive in the body after initial infection, it also has been linked to later development of some autoimmune diseases and rare cancers.

It’s not clear why. Among the possibilities is what’s called “molecular mimicry,” meaning viral proteins may look so similar to some nervous system proteins that it induces the mistaken immune attack.

The new Harvard research wasn’t a randomized trial that could prove cause and effect, but the link suggested by the findings makes it “the strongest evidence to date that Epstein-Barr contributes to cause MS,” said Mark Allegretta, vice president for research at the National Multiple Sclerosis Society.

And that, he added, “opens the door to potentially prevent MS by preventing Epstein-Barr infection.”

Attempts are underway to develop Epstein-Barr vaccines, including a small study just started by Moderna, the company now best known for its COVID-19 vaccine.

Multiple sclerosis caused by Epstein-Barr-Virus: Study

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Multiple sclerosis (MS) is an unpredictable condition — an autoimmune disease that attacks the central nervous system, the brain and spinal cord.

MS tends to hit people in the prime of their lives. In most cases, the disease starts when those afflicted are between 20 and 40 years old.

It can be mild but can also turn into a lifelong disability, affecting a person’s vision, arm or leg movement, sensation or balance.

And until now researchers have not known conclusively what causes MS. There are treatments to make living with MS better, perhaps easier, but there is no cure.

But that may change now that researchers say they have found a link between Epstein-Barr-Virus and MS. That could open the door to better treatments and even preventative measures.

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The link between Epstein-Barr-Virus and MS

In a study conducted in the United States, researchers say they found that the Epstein-Barr-Virus (EBV) was definitely associated with all but one of 801 cases of multiple sclerosis.

The researchers analysed blood samples from more than 10 million US military employees and identified 801 people with multiple sclerosis. They then analysed those blood samples — from the people with MS — for EBV antibodies. That would indicate whether those people had ever had an EBV infection.

Epstein-Barr-Virus causes glandular fever, which commonly affects teenagers and young adults. It causes swollen glands and sore throat, and you usually only get it once in your life.

Among those US military personnel, 35 people with MS showed no EBV antibodies in an initial blood sample. But the researchers say that 34 of those 35 people later tested positive for EBV antibodies.

Only one of the 801 people with MS ultimately tested negative for EBV antibodies.

The most important indicator appears to be that those people who had initially tested negative for EBV antibodies also tested negative for multiple sclerosis at the time of the blood sample. It was only after those people experienced an EBV infection that they developed MS, which was also then detected by the researchers.

ALSO READ | Having MS and depression may be tied to increased risk of death: Study

So, the researchers seem confident there is a link between EBV and MS. What they still don’t know, however, is EBV’s precise mechanism — or what it does exactly to cause MS and why.

EBV does not automatically mean MS

It’s important to note that while about 90% of people contract EBV or glandular fever at some point in their lives, only very few develop multiple sclerosis.

However, experts say the new research and its data are significant.

“The study uses epidemiological methods to assess the risk of developing MS after an infection with the Epstein-Barr-Virus. And the authors conclude that the risk of developing MS is 32 times higher among people who have had EBV than those who have not,” said Henri-Jacques Delecluse, a leading researcher at the German Cancer Research Centre. “That is a significant number. It’s the sort of risk we see for lung cancer among smokers.”

But Roland Martin, a leading researcher at University Hospital Zurich, says it’s too early to conclude that EBV is the main cause of MS.

“The methodology is good and solid, and you could conclude that EBV is the main cause of MS,” said Martin. “But for me, that goes too far. Over the past 20 years, our data has indicated that MS has a complex genetic background, one that can make you more prone to developing MS.”

So, it may not only be EBV or genetics, but a combination of the two.

ALSO READ | Study: Childhood trauma affects development, treatment of multiple sclerosis

Symptoms: What should you do if you’re concerned?

As with every health issue: For the best advice, ask a medical professional or a doctor you trust if you’re concerned.

Symptoms for multiple sclerosis can differ from person to person. But they can include the following:

Numbness or weakness in one or more limbs

Electric-shock sensations when you move your neck

Tremors or lack of coordination when you walk

Problems with vision, double vision and pain in your eyes

Slurred speech

Fatigue

Dizziness

Problems with sexual, bowel and bladder function

The study is published in the journal Science.

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Study: More evidence links a virus to multiple sclerosis

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They tracked blood samples stored from more than 10 million people in the U.S. military and found the risk of MS increased 32-fold following Epstein-Barr infection.

The military regularly administers blood tests to its members and the researchers checked samples stored from 1993 to 2013, hunting antibodies signaling viral infection.

Just 5.3% of recruits showed no sign of Epstein-Barr when they joined the military. The researchers compared 801 MS cases subsequently diagnosed over the 20-year period with 1,566 service members who never got MS.

Only one of the MS patients had no evidence of the Epstein-Barr virus prior to diagnosis. And despite intensive searching, the researchers found no evidence that other viral infections played a role.

It’s clearly not the only factor, considering that about 90% of adults have antibodies showing they’ve had Epstein-Barr – while nearly 1 million people in the U.S. are living with MS, according to the National Multiple Sclerosis Society.

Regardless, the new study is “the strongest evidence to date that Epstein-Barr contributes to cause MS,” said Mark Allegretta, vice president for research at the National Multiple Sclerosis Society.

And that, he added, “opens the door to potentially prevent MS by preventing Epstein-Barr infection.”

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

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

Could the ‘Mono’ Virus Help Trigger Multiple Sclerosis?

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It all hints that something about the immune response to EBV infection can, in certain people, prompt the development of MS.

But proving the virus is a cause of MS, and not just a bystander, has been challenging. That’s partly because nearly everyone is infected with EBV, while MS is relatively rare.

It takes a massive and long-term study to identify people who are initially EBV-negative, then see whether a new EBV infection raises their risk of subsequently developing MS.

The new study, published in the journal Science, did just that.

“This is the strongest evidence we have to date that EBV contributes to MS,” said Mark Allegretta, vice president of research for the nonprofit National MS Society.

Allegretta, who was not involved in the study, said the virus is likely “necessary, but not sufficient” to cause MS. That is, it conspires with other factors that make people more vulnerable to developing MS.

At this point, studies have identified some other factors linked to higher MS risk, said study senior author Dr. Alberto Ascherio.