Multiple sclerosis (MS), a progressive disorder for which there is no definitive cure, is very likely caused by the Epstein-Barr virus (EBV), according to a recent study published on January 13 by researchers at the Harvard TH Chan School of Public Health. EBV is classed as a herpes virus that can induce infectious mononucleosis within its host and establish a latent, lifelong infection. In the early 2000s, Alberto Ascherio, now professor of epidemiology and nutrition at Harvard Chan School, found evidence of EBV being a potential causative factor of MS as the virus was located in the demyelinated death zones of MS patients. The recent study has given more conclusive evidence of this link. To determine the relationship between the two conditions, the researchers analysed over ten million young adults who had enrolled on active duty for the US military. The study involved analysing three blood samples for each individual. The first sample was taken before patients reached age 20 years, the last was taken years later but still before the onset of MS and one sample was taken in between.

Among the cohort, researchers identified 955 individuals with MS and found the risk of MS onset to increase 32-fold after infection with EBV. This was assessed by showing that serum levels of neurofilament, a biomarker for neurodegeneration, had increased significantly after infection with EBV, while it did not after infection with other viruses. Ascherio, the senior author of the study, stated that “this is a big step because it suggests that most MS cases could be prevented by stopping EBV infection and that targeting EBV could lead to the discovery of a cure for MS.”

Despite this, questions remain about whether EBV is the sole cause of MS. EBV typically affects a majority of the population, but MS is a condition that only affects 2.8 million people. Researchers have concluded that MS is likely a multifactorial disease, with previous studies revealing that particular genes can also increase its prevalence. There are also other environmental aspects such as vitamin D deficiencies that can lead to early symptom progression. Michael Wilson, a neurologist at the University of California, argues that while “EBV probably isn’t the whole story, this study helps show it’s clearly part of it. The exciting thing is that it’s a modifiable part of the story.” Currently, there are no vaccines available for EBV as the virus itself has presented technical hurdles in the past and was never life-threatening. However, with the recent study results, there is now a new incentive to begin development on a vaccine. As a result, future prevention methods could involve becoming vaccinated against EBV, which may be a catalyst in reducing MS prevalence.