Following a request from the European Commission, ECDC produced in July 2011 a risk assessment to assess the possible implications of XMRV on blood donation. A review of the published literature at the time showed that there is not enough evidence to reliably assess the potential role of the virus in human pathology.
Many questions remain regarding the possible prevalence of XMRV in the human population, the incidence of XMRV in cases of CFS and the extent of genetic variation between XMRV isolates. Although it is theoretically presumed that XMRV could be transmitted through blood transfusion, no such transmission event has been identified, and there is no known evidence of XMRV infection, related illness or disease in transfusion recipients. XMRV may represent another emerging infectious agent that poses a risk to transfusion safety, and as with other agents, it is imperative that the action taken to ensure blood safety is swift and effective, yet based on the best available science. Currently, the scientific data are incomplete and conflicting. It seems likely that the findings in two studies on XMRV and murine leukemia virus in CFS patients were potentially due to laboratory contamination, and the majority of the evidence favours the conclusion that there is no causal relation between XMRV and CFS. With the development of validated assays, additional data will become available in the near future which will help inform decisions on blood donor eligibility and screening.
