Alter, Harvey J, Mikovits, Judy A, Switzer, William M et al. · mBio · 2012 · DOI
Earlier studies suggested that two viruses (XMRV and pMLV) might cause ME/CFS, but this finding was controversial. In this study, the same scientists who originally reported finding these viruses carefully re-examined blood samples from 147 ME/CFS patients and 146 healthy people without knowing which samples came from which group. They found no evidence that either virus was present in any of the samples, meaning the original finding could not be confirmed.
This study demonstrates scientific self-correction and provides reassurance that these particular viruses are not the cause of ME/CFS, allowing research resources to be redirected toward more promising leads. The rigorous blinded methodology establishes an important precedent for definitively addressing disputed pathogen discoveries, reducing persistent uncertainty that can affect patient confidence and research priorities.
This study does not prove that ME/CFS has no viral cause—only that these two specific viruses are not involved. It does not establish the actual etiology of ME/CFS, nor does it explain why the original studies reported positive findings. The study's negative findings do not address whether other pathogens might play a role in ME/CFS pathogenesis.
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 →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Alter, Harvey J, Mikovits, Judy A, Switzer, William M, Ruscetti, Francis W, Lo, Shyh-Ching, Klimas, Nancy, et al. (2012). A multicenter blinded analysis indicates no association between chronic fatigue syndrome/myalgic encephalomyelitis and either xenotropic murine leukemia virus-related virus or polytropic murine leukemia virus.. mBio. https://doi.org/10.1128/mBio.00266-12
BibTeX
@article{mecfsatlas-alter-2012-multicenter-blinded,
author = {Alter, Harvey J and Mikovits, Judy A and Switzer, William M and Ruscetti, Francis W and Lo, Shyh-Ching and Klimas, Nancy and Komaroff, Anthony L and Montoya, Jose G and Bateman, Lucinda and Levine, Susan and Peterson, Daniel and Levin, Bruce and Hanson, Maureen R and Genfi, Afia and Bhat, Meera and Zheng, HaoQiang and Wang, Richard and Li, Bingjie and Hung, Guo-Chiuan and Lee, Li Ling and Sameroff, Stephen and Heneine, Walid and Coffin, John and Hornig, Mady and Lipkin, W Ian},
title = {A multicenter blinded analysis indicates no association between chronic fatigue syndrome/myalgic encephalomyelitis and either xenotropic murine leukemia virus-related virus or polytropic murine leukemia virus.},
journal = {mBio},
year = {2012},
doi = {10.1128/mBio.00266-12},
note = {PubMed: 22991430},
url = {https://www.mecfsatlas.com/evidence/alter-2012-multicenter-blinded},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/alter-2012-multicenter-blinded
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