Sadly, another study has been published where the resulting data did not support XMRV (xenotropic murine leukemia virus–related virus) as a cause of Chronic Fatigue Syndrome (CFS).
This study did all the controls the other conflicting studies had not: used the same PCR primers, the same experimental standards, the same patient criteria. However, scientists are not giving up on XMRV yet. They are going to try to get more standardized testing infrastructure established to make sure the test parameters are uniform. However, at this point they do feel that the anti-viral therapy that had been suggested for CFS may be premature.