Boston, MA – Multiple sclerosis (MS), a progressive disease that affects 2.8 million people worldwide and for which there is no definitive cure, is likely caused by infection with the Epstein-Barr virus (EBV), according to a study led by Harvard T.H.

Chan School of Public Health researchers.

Establishing a causal relationship between the virus and the disease has been difficult because EBV infects approximately 95% of adults, MS is a relatively rare disease, and the onset of MS symptoms begins about 10 years after EBV infection.

Ascherio says that the delay between EBV infection and the onset of MS may be partially due to the disease’s symptoms being undetected during the earliest stages and partially due to the evolving relationship between EBV and the host’s immune system, which is repeatedly stimulated whenever latent virus reactivates.

Other Harvard Chan School researchers who contributed to this study include Kjetil Bjornevik, Marianna Cortese, Michael Mina, and Kassandra Munger.

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