Scientists Announce Big Find on Multiple Sclerosis

Researchers say more treatments for multiple sclerosis may be possible after finding a likely "initial trigger" of the auto immune disease. It's unknown what exactly causes MS, a condition affecting 2.8 million people in which immune system cells attack the protective coating on nerve fibers, though some have theorized a link with Epstein-Barr virus, a member of the herpes virus family known to cause mononucleosis (aka mono) and other illnesses. In a new study, Harvard researchers say they've found compelling evidence of that link. They analyzed blood samples taken from more than 10 million US military employees from 1993 to 2013, including 801 people with multiple sclerosis. Of those MS patients, all but one had EBV antibodies.

Most people become infected with EBV, which may be symptomless, at some point in their lives, often as kids or young adults, according to the CDC. Only about 5% of military recruits lacked EBV antibodies, per the AP. Part of what is driving the researchers' confidence: The New York Times reports that because the study covered a 20-year period, scientists were able to look at the small number of military employees who weren't infected with EBV initially but later did become infected. In the MS group, 32 of 33 patients experienced that late EBV infection before developing MS. The findings "strongly suggest" EBV is "a cause and not a consequence of MS," Dr. Alberto Ascherio and colleagues write in the journal Science.

In fact, the "risk of MS increased 32-fold after infection with EBV but was not increased after infection with other viruses." As EBV researcher Henri-Jacques Delecluse tells Deutsche Welle, "it's the sort of risk we see for lung cancer among smokers"—though some researchers believe genetics also play a role. This "opens the door to potentially prevent MS by preventing Epstein-Barr infection," Mark Allegretta, vice president for research at the National Multiple Sclerosis Society, tells the AP. Moderna is developing an EBV vaccine, while BioNTech is developing an MS treatment that won't suppress the immune system. (More multiple sclerosis stories.)