Possible that prednisone can increase viral replication. However, prednisone is immunosupressive so seperating out the induction of viral replication by prednisone as oppesed to immunesupressive effects would be difficult.
For those interested in this question, it doesn't address progesterone but there have been studies (even trials) of hydrocortisone and CFS in the past with some mixed results. Check out Pubmed. I would caution people to be careful about using steroids solely for treatment of CFS as there are serious side effects of long-term steroid use aside from its possible effects on XMRV.
I got sick when I was very young. I'm not sure when, but younger than 5 or 6 (before I can remember).
Apparently at one time, I got a hold of my mother's birth control pills and ate the whole months worth in one shot (I guess I thought it was candy). This is a bit of a leap, but I now wonder if this had anything to do with me getting sick.
And it also makes me wonder if women get this more because of the 'pill'.