Virus may cause virtually all cases of multiple sclerosis

Virtually every case of multiple sclerosis (MS) is preceded by an infection with the Epstein-Barr virus (EBV), a new study has found.

Known as glandular fever, the EBV has long been a suspected trigger for MS. The virus is a type of herpes and is spread via saliva, which is why it’s known colloquially as the kissing disease.

The trouble with ascertaining whether EBV is what causes MS is it’s thought that 9 in 10 people from the general population become infected with it. It remains as a lifelong infection. Most people don’t know they’ve been infected but for some people, it causes glandular fever. This in turn means huge numbers of people would need to be monitored to discover whether the people who have not been infected are less likely to get MS.

In this 20-year study, researchers looked at 10 million American military personnel who had blood samples taken from them regularly and then stored, allowing testing for EBV. Just 5% of the participants were infected at first blood sample collection. Out of the 10 million, 955 went on to develop MS, on average about 10 years after the first blood sample, but only one single person from this 955 tested negative for EBV antibodies. Another 34 were uninfected when their first blood sample was taken, but became infected before being diagnosed with MS.

“The hypothesis that EBV causes MS has been investigated by our group and others for several years, but this is the first study providing compelling evidence of causality,” said Alberto Ascherio, professor of epidemiology and nutrition at Harvard Chan School and senior author of the study. “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.”

“The hypothesis that EBV causes MS has been investigated by our group and others for several years, but this is the first study providing compelling evidence of causality,” said Alberto Ascherio, professor of epidemiology and nutrition at Harvard Chan School and senior author of the study. “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.

“This is really a turning point,” he says. “It should lead to better ways to treat MS as well as help to prevent it.”

Several companies are currently trying to develop a vaccine against EBV, with Moderna announcing earlier this month it has begun testing a possible vaccine on people.