The National Cancer Institute has responded to the recent news of the XMRV and ME/CFS link, thanks to a request by the CFIDS Association. The CFIDS Association was asking for guidelines for ME/CFS patients, their families, and for the general public regarding their thoughts on XMRV. Here is the response from the National Cancer Institute, as it is posted on the CFIDS Association Facebook page.
We at the National Cancer Institute (NCI) have great interest in these initial research findings. At present, we agree that a critical issue to be addressed is whether the exciting recent results obtained using samples from the Nevada cohort can be reproduced in additional cohorts of CFS-afflicted individuals. The NCI is striving to develop tools so that the general prevalence of XMRV in the population can be ascertained, and the association of XMRV with disease can be examined.
In the meantime, it is very important to reiterate what we do not know at this point, specifically:
1. We do not know whether XMRV is a causative agent for CFS, prostate cancer, or any other disease. Even if a causal association can be established, it may be only one of many causes, and there may be other factors, genetic or environmental, that determine the outcome of infection. At the moment, there is no evidence of CFS transmission between family members, even though XMRV appears to be an infectious agent. Thus, it is unclear whether XMRV alone underlies CFS.
2. We do not know how XMRV is transmitted from individual to individual. Recent suggestions of sexual or salivary transmission are not based on direct evidence, and conclusions regarding transmission are not credible at this point. Given the frequent isolation of virus from white blood cells, blood-borne transmission is a real possibility, and, while we are not in a position to establish firm guidelines, prudence would dictate that potentially infected individuals refrain from blood donation at this time.
3. We do not know how many apparently healthy individuals are infected, and what the distribution of infection is within the U.S. and in the worldwide population. The National Cancer Institute is involved in coordinating a global effort to study these issues.
It is very important to keep in mind that there is no evidence for a new increasing or spreading XMRV infection. Further, no credible evidence exists for direct transmission of either CFS or prostate cancer.
John E. Niederhuber, M.D.
Director, National Cancer Institute
National Institutes of Health
U.S. Department of Health and Human Services
October 23, 2009
Note: According to Dr. Wanda Jones of DHHS, these issues will be discussed by representatives from DHHS, NIH and other federal health agencies at the upcoming federal CFS Advisory Committee meeting on Oct. 29-30.