Kissing disease: Mononucleosis linked to increased risk of multiple sclerosis, study finds

A US study has found that people who develop infectious mononucleosis, commonly known as the “kissing disease”, may be more than three times more likely to develop multiple sclerosis (MS) later in life. The research, based on records from the Mayo Clinic-led Rochester Epidemiology Project tracking nearly 19,000 individuals, found that the risk remains low in absolute terms but is statistically higher among those who had mono.

Researchers reported that 0.17% of individuals with mononucleosis went on to develop MS, compared with 0.07% among those without the infection. Cases of MS also appeared earlier in people who had previously been infected with the Epstein-Barr Virus (EBV), which causes mono and is one of the most common human infections worldwide.

Experts, however, stressed that the link does not imply causation. Neurologists noted that while EBV is strongly associated with MS, it is not sufficient on its own to cause the disease, which typically develops due to a combination of genetic, environmental and immune factors.


Dr Sudhir Kumar, neurologist at Apollo Hospital, Hyderabad, said the apparent rise in younger MS cases is more likely due to improved awareness and earlier MRI-based diagnosis rather than a true shift in disease onset. He added that EBV may act as a trigger only in genetically susceptible individuals.

He also cautioned against routine long-term monitoring of people after mononucleosis, noting that the absolute risk of developing MS remains low and unnecessary screening could cause anxiety. Instead, he emphasised awareness of early neurological symptoms.

These symptoms may include blurred or painful vision, tingling or numbness, unexplained fatigue, brief weakness, imbalance, or a shock-like sensation down the spine. Experts advised that any neurological symptom lasting more than 24 hours should be medically evaluated.

Prof Manjari Tripathi, head of neurology at AIIMS Delhi, said EBV is widespread in India, especially among children and adolescents. She noted that MS is a complex condition influenced by multiple risk factors and reiterated that most people infected with EBV never develop the disease.

Scientists said the findings strengthen interest in preventive approaches, including the development of a potential EBV vaccine.