Chronic Controversy Continues Over Mysterious XMRV Virus

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Chronic controversy continues over mysterious XMRV virus Last year, a Nevada team linked a peculiar retrovirus to chronic fatigue syndrome (CFS), an elusive condition with no known cause. The virus—known as xenotropic murine leukemia virus–related virus, or XMRV—had previously been implicated in an aggressive form of prostate cancer, but XMRV’s role in both diseases has been hotly contested, particularly with regard to CFS. Several research groups have failed to reproduce the initial finding, including a team from the US Centers for Disease Control and Prevention (CDC), but scientists at the National Institutes of Health (NIH) and Food and Drug Administration (FDA) reportedly have unpublished data supporting the link between the mysterious virus and CFS. “When the data are published, they will provide a confirmation of our initial discovery,” says Judy Mikovits, director of research at the Whittemore Peterson Institute in Reno, Nevada who led the research. Spurred on by these mixed results, the FDA’s blood products advisory committee met for two days in late July to discuss whether the virus poses a safety threat to the blood supply. Here are the facts they had to consider:

18 June: The US American Three independent research teams—two from 14 May: The Dutch team and Association of Blood the UK and one from the Netherlands—failed two more research groups Banks joins Canadian, to detect significantly elevated levels of XMRV from the UK and Australia Australian and New genetic material in their own samples from a challenge the original paper’s Zealand officials in total of 388 people with CFS (PLoS One 5, methodology in a series of recommending against e8519, 2010; Retrovirology 7, 10, 2010; BMJ technical papers in Science blood donation from people with 340, c1018, 2010). (328, 825, 2010). CFS.

October 2009 April 2010 June 2010 January–February 2010 May 2010 July 2010

8 October: Mikovits and 6 April: Canada becomes 1 July: A team from the CDC 26 May: The NIH’s Harvey Alter her colleagues report the first country to fail to detect XMRV in blood allegedly announced at a closed traces of XMRV DNA in recommend that individuals specimens from 51 individuals meeting in Zagreb, Crotia that NIH the white blood cells with CFS should not donate with CFS and 56 healthy people and FDA scientists had independently of 67% of a group of blood or blood products (Retrovirology 7, 57, 2010). confirmed the link between XMRV and 101 people with for fear of passing on the Meanwhile, a paper reportedly CFS. In his PowerPoint presentation, CFS, compared with suspected virus. accepted in the Proceedings of the Alter wrote that the data in the only 4% of healthy National Academy of Sciences USA 2009 Science paper “are extremely controls (Science describing the NIH-FDA findings strong and likely true, despite the 326, 585–589, 2009). is delayed for publication while controversy,” according to the Dutch the researchers conduct additional nutrition and food supplement experiments. magazine Ortho.

Immunization rates against the human afford the vaccine,” says Marc Steben, a comparable to three doses in preventing papillomavirus (HPV), the virus that medical consultant at Quebec’s National infection from two of the cancer-causing causes cervical cancer, are amongst the Public Health Institute in Montreal. strains of HPV. lowest of all vaccine programs in the US, Some of the first evidence that this Simon Dobson, a pediatric vaccine with fewer than one in four female teens strategy might be effective came last researcher at the University of British getting the shot in many poor-income month at the International Papillomavirus Columbia in Vancouver, reported results states, and often far fewer women than Conference in Montreal. At the meeting, from a more deliberately planned study of that get immunized in countries of the Aimée Kreimer, an investigator at the US dosing routine. He showed that Canadian developing world. A major deterrent, National Cancer Institute in Bethesda, girls aged 9–13 who had received two public health experts warn, is the Maryland, presented results from a four- doses of Merck’s competing vaccine vaccine’s price—the two approved HPV year study of nearly 7,500 women in Costa Gardasil had antibody responses to the two vaccines are among the most expensive Rica treated with either GlaxoSmithKline’s main cancer-causing HPV strains that were adult vaccines, often costing close to (GSK’s) HPV vaccine Cervarix or a control at least as good as those in women aged $400 in the US private sector for a full vaccine. Although the researchers planned 16–26 who had received three doses of the three-dose course of therapy. To bring to administer the full three-dose treatment, vaccine. down costs, researchers are investigating around 1,500 women received fewer According to Steben, reducing whether women are afforded the same than three doses, owing to missed visits, vaccination costs by a third could protection with an abridged vaccine pregnancy or other reasons. Kreimer and particularly help middle income countries regimen. her colleagues tracked the majority of that currently have no access to GAVI “If you reduce the cost, it may mean these women nonetheless and found that a Alliance–sponsored cheap HPV shots, such that many more countries are able to one- or two-shot treatment of Cervarix was as some in Eastern Europe, South America

832 volume 16 | number 8 | august 2010 nature medicine