Published: September 7, 2023
Estimated reading time: 3 minutes
A study led by a team of Harvard scientists shows strong evidence that Epstein-Barr virus (EBV) is the leading cause of multiple sclerosis (MS), shedding new light on a mystery that has stumped doctors and researchers for decades.
MS is an autoimmune disease. The body’s immune system mistakenly attacks the myelin sheaths that surround and protect nerves. Symptoms include numbness, tingling, blindness and paralysis. The symptoms of MS range from very mild to severe and vary from person to person. There is virtually no way to predict the progression of MS, and there is no known cure.
According to the Centers for Disease Control and Prevention, EBV is one of the most common human viruses in the world. Spread through saliva, EBV can cause other infections, such as mononucleosis (mono). EBV often is spread among children and young adults, since it is easily passed from person to person and often has no symptoms.
Children are often infected with EBV with no symptoms, or symptoms that resemble any mild childhood illness.
“This is one of the more promising discoveries linking the two diseases,” said Geeta A. Ganesh, M.D., MPH, neurologist with Norton Neuroscience Institute Hussung Family Multiple Sclerosis Center. “Other viruses have been studied, but EBV seems to have the strongest prevalence associated with MS.”
From diagnosis through treatment, Norton Neuroscience Institute providers support multiple sclerosis patients along the way.
MS has been associated with people who’ve had mono, which is caused by EBV. A 2007 study found that risk of MS can increase soon after a mono infection and persist for at least 30 years.
Indeed, the more recent study suggesting EBV as the leading cause of MS found that people infected with EBV were 32 times as likely to develop MS as those who hadn’t been infected. Other viruses, including a very similar virus, did not increase the risk of MS.
The study found that as many as a quarter of MS patients have antibodies that latch on to a protein from EBV as well as a protein in the myelin sheaths. Essentially, the immune system attacks the EBV, but mistakes the similar protein in myelin and winds up attacking that as well.
Having EBV itself isn’t enough to trigger MS. The virus is thought to work in conjunction with certain genetic factors.
While the discovery clears up some of the mystery around the cause of MS, there are still many questions. It is not known if EBV causes relapses or affects the progression of MS. Though EBV is a trigger, MS is fueled by a combination of genetics, environment and other factors. Research has yet to establish a link between EBV and any particular type of MS.
More encouraging news lies in the potential of an EBV vaccine that would prevent the disease and possibly could protect those who already have a higher risk for MS. That includes people whose close family members have MS.
There are about 200 genes that each add to the risk of developing MS. In identical twins, if one twin develops MS, the chances of the other twin getting the disease is about 1 in 4. The risk of developing MS in the general population is about 1 in 334.