Coffin, John M, Kearney, Mary F · Annual review of virology · 2024 · DOI
In 2009, scientists found a virus called XMRV in some people with ME/CFS, which created excitement that they might have discovered a cause of the illness. However, when researchers around the world tried to confirm this finding, they repeatedly could not—and eventually realized the virus had contaminated the laboratory samples with mouse virus rather than coming from patients. This article tells the story of how this discovery was made, why it turned out to be false, and what we learned from this experience.
This study is important because it documents a significant moment in ME/CFS research history where initial promising leads about a viral cause did not hold up to scrutiny. Understanding how and why these findings failed helps the research community improve laboratory practices, strengthen validation procedures, and builds caution about drawing premature conclusions—ultimately protecting future ME/CFS research integrity and patients' trust in the scientific process.
This editorial does not prove that XMRV plays no role in any human disease, nor does it establish that other viral or infectious agents are not involved in ME/CFS pathogenesis. It also does not address what the actual biological cause(s) of ME/CFS may be—it only documents why one particular hypothesis was not supported by reproducible evidence.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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