Yes, that is the million dollar question.
I would like to know: out of those people that said that had CFS/ME symptoms for a up to a year or so from an initial triggering viral infection, and then got full remission, how may of those had Epstein-Barr virus as their trigger?
Chronic EBV infections can last a long time, and do cause the CFS/ME state while the infection is ongoing, but these chronic EBV infections do eventually resolve on their own. So if this happens to someone, they are going to think that they had CFS/ME, and got full remission, whereas in fact they just followed the normal course of chronic EBV infections: ie, the EBV infection precipitated the CFS/ME state for a while, followed by a pretty much guaranteed recovery.
Does anyone have any info on how many recovered people might have just had chronic EBV infection, rather than proper CFS/ME?
Another interesting case of remission is that of Dr John Chia's son, Andrew Chia. I read that Andrew got remission after (I think) interferon therapy for an enterovirus-associated CFS/ME. He was fine, until he went on a mountain hiking holiday I believe, where the constant day-after-day physical exertion of mountain hiking brought back his symptoms, and a relapse.
The trick, it would seem, if you do get remission, is not to push your luck, and go do too many exerting things.