Resolve to scientific consensus whenever that is reached. Will resolve conservatively (i.e. lean towards leaving it open for another year).
Note that, from trevorklee, "More importantly, however, we don’t know the rest of the factors that contribute to MS. 90% of adults in the US have had EBV, while only 0.3% of adults have MS. There must be other factors that make those 0.3% get MS while the other 89.7% do not, but it’s unclear what they are."
so this resolves YES if EBV causes the risk of getting MS if you have had EBV to be much higher than without EBV and NO otherwise
From Derek Lowe, there's increasing evidence for EBV being a causative factor: https://www.science.org/content/blog-post/ebv-and-multiple-sclerosis-more-story.
I don't know if the latest developments are sufficient to resolve this market or not.