New Findings ‘Strongly Suggest’ Epstein-Barr Virus May Help Trigger Multiple Sclerosis
There is new evidence that one of the most common viruses in the world can put some people on the path to developing multiple sclerosis (MS).
The potentially disabling disease occurs when cells of the immune system mistakenly attack the protective coating of nerve fibers, gradually eroding them.
The Epstein-Barr virus, a widely distributed human herpes virus, has long been suspected to play a role in the development of MS. This is a difficult link to prove because just about everyone is infected with Epstein-Barr, usually in children or young adults, but only a tiny fraction develops MS.
Harvard University researchers on Thursday reported one of the largest studies to date to support Epstein-Barr’s theory.
They tracked blood samples stored from more than 10 million people in the US military and found that the risk of MS was increased 32-fold after infection with Epstein-Barr.
The military regularly administers blood tests to its members, and researchers checked samples stored from 1993 to 2013, chasing antibodies signaling a viral infection.
Only 5.3% of recruits showed no sign of Epstein-Barr when they joined the military. The researchers compared 801 cases of MS subsequently diagnosed over the 20-year period with 1,566 servicemen who never contracted MS.
Only one of the MS patients had no signs of Epstein-Barr virus before diagnosis. And despite intensive research, researchers have found no evidence that other viral infections played a role.
The results “strongly suggest” that Epstein-Barr infection is “a cause and not a consequence of MS,” reported study author Dr. Alberto Ascherio of the Harvard TH Chan School of Public Health and colleagues in the journal Science.
Virus best known to cause “mono”
This is clearly not the only factor, given that about 90% of adults have antibodies showing they have had Epstein-Barr – while nearly a million people in the United States 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 that approximately 90,000 Canadians are living with the disease, or one in 400 people.
The virus appears to be “the initial trigger,” according to Drs. William H. Robinson and Lawrence Steinman of Stanford University wrote in an op-ed accompanying Thursday’s study. But they warned that “more fuses need to be turned on,” such as genes that can make people more vulnerable.
Epstein-Barr is best known for causing “mono,” or infectious mononucleosis, in adolescents and young adults, but often occurs without any symptoms. A virus that remains inactive in the body after the initial infection, it has also been linked to the later development of certain autoimmune diseases and rare cancers.
We do not know why. Among the possibilities is something called “molecular mimicry”, which means that viral proteins can look so similar to certain proteins in the nervous system that they induce a false immune attack.
The new Harvard research was not a randomized trial that could prove cause and effect, but the link suggested by the results makes it “the strongest evidence to date that Epstein-Barr contributes to the cause of MS “said Mark Allegretta, vice president of 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.