Yes there are and have been outbreaks of CFIDS/ME. Plenty of cluster cases. And when I got sick in 91, I got it from a guy I was dating, through casual contact, kissing/saliva, no sex. And when I went to my doctor then, he said there was a huge outbreak of it in my county, he was seeing tons of cases of it, and he knew right away that I had it.
My belief has always been that it is only infectious during the first thirty days. Maybe there are other strains of it that are different. But the one that got me, I think that's the one spreading all over China now.