This has been my view all along. Looking at risk factors, transmission possibilities, the different modes of disease onset, and my own experience, I believe contaminated vaccine is the most likely source.
My thoughts: Overachiever (chronic stress) is our dominant personality trait and supposedly xmrv loves cortisol. We have both clusters and isolated cases. Onset almost always follows Immune stress and trauma, but not always as an infection. And, we have government health agencies strongly resisting discovery of the cause of this illness. I did not have an infectious onset....it was triggered by stress and the Hep B vaccine. Since I had 25 years of excellent health prior to onset, whatever was triggered had most likely been there (latent) for many years. I believe I contracted xmrv one of 2 ways....vertically, or via contaminated vaccine in childhood. I lean heavily to the latter.
Dr Judy has suggested vaccine as a trigger:
"On that note, if I might speculate a little bit," she said, "This might even explain why vaccines would lead to autism in some children, because these viruses live and divide and grow in lymphocytes -- the immune response cells, the B and the T cells. So when you give a vaccine, you send your B and T cells in your immune system into overdrive. That's its job. Well, if you are harboring one virus, and you replicate it a whole bunch, you've now broken the balance between the immune response and the virus. So you have had the underlying virus, and then amplified it with that vaccine, and then set off the disease, such that your immune system could no longer control other infections, and created an immune deficiency."