Neurology Open Access
Mono linked to higher multiple sclerosis risk
Clinical takeaway: Mononucleosis may heighten risk for multiple sclerosis; EBV-positive mono was associated with roughly a 3-fold higher MS risk.
Epstein-Barr virus is increasingly implicated as a key trigger for multiple sclerosis. New data suggest that symptomatic infection, in the form of mononucleosis, may help identify patients at higher risk.
EBV is nearly ubiquitous and usually asymptomatic, but infection in adolescence or adulthood can cause infectious mononucleosis (mono). This study links that higher-intensity exposure to increased MS risk, though causation is not established.
MS developed in 8 patients with mono (0.17%) vs. 10 without (0.07%) among 4,721 patients with mono and 14,163 matched controls. The mono group had shorter follow-up (median, 6 vs. 8 years). Incidence rates adjusted for time at risk were higher in the mono group (2.25 vs 0.77 per 10,000 person-years), with an adjusted hazard ratio of 3.14.
EBV is increasingly viewed as a necessary, but not sufficient, trigger for MS, with additional genetic and environmental factors determining who develops disease.
“Preventing these infections could reduce the overall burden of MS,” said study author Jennifer St. Sauver of the Mayo Clinic.
Source: St. Sauver JL, et al. Neurology Open Access. April 1, 2026. Risk of Multiple Sclerosis Among Persons With Epstein-Barr Virus–Positive Mononucleosis: A Population-Based Study