Prospective studies on post-infective cohorts, like Dubbo, are focused on the difference between those that recover normally from Glandular Fever etc, typically within a few months, and those that do not and go on to develop CFS. They're well set up to look at what goes on in the first 6 months or so of illness. As you say, most of these CFS patients then recover within 2 years. I would be interested to know how CFS patients from such studies compare with other CFS patients at the same stage. In other words, if you took a group of patients who had just reached the 6-month CFS threshold and followed them for the next 2 years, what would their recovery rates be like, and would they be significantly different from Dubbo? All the prognosis studies I've seen start with patients who on avearge have been ill for quite a few years.