The “Heal with Liz” video channel has an interview with Phil who recovered from ME/CFS after 8 years and he talks about his journey through the illness to where he is now.
All the current anecdotal and research evidence indicates that while complete and sustained recovery from ME/CFS does occur in adults it is fairly unusual. The better news is that recovery seems to be far more common in children and adolescents, especially where there has been good management and proper educational support. My gut feeling is that there is a genetic predisposition to developing ME and this does not go away. So it is perfectly possible to recover from one episode of ME but then have another episode if you have another infection and this is combined with some other factor involving the immune system response at the time that we don't fully understand.
Dr Charles Shepherd
More information
The MEA have a leaflet covering prognosis for those with ME/CFS.