Hannestad, Ulf, Allard, Annika, Nilsson, Kent et al. · Viruses · 2025 · DOI
This study tested sputum (saliva and mucus) samples from ME/CFS patients and healthy people to look for viruses and signs of immune dysfunction. Researchers found that ME/CFS patients had significantly higher levels of Epstein-Barr virus (EBV) compared to controls, but surprisingly, most people carried human herpesvirus 6 at similar levels. The study suggests that ME/CFS patients may have trouble fighting off viruses, but this isn't simply due to the immune system attacking itself.
Understanding why ME/CFS patients have persistent viral reactivation and impaired antiviral immunity is crucial for developing targeted treatments. This study provides evidence that the mechanism may involve viral strategies to evade interferon response rather than simple autoimmunity, opening new research directions for intervention.
This study does not prove that EBV reactivation causes ME/CFS, only that it is more frequently present in sputum. The cross-sectional design cannot establish causality or determine whether elevated EBV is a cause, consequence, or marker of disease. It also cannot rule out other immune dysfunction mechanisms beyond those tested.
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
Hannestad, Ulf, Allard, Annika, Nilsson, Kent, & Rosén, Anders (2025). Prevalence of EBV, HHV6, HCMV, HAdV, SARS-CoV-2, and Autoantibodies to Type I Interferon in Sputum from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients.. Viruses. https://doi.org/10.3390/v17030422
BibTeX
@article{mecfsatlas-hannestad-2025-prevalence-ebv,
author = {Hannestad, Ulf and Allard, Annika and Nilsson, Kent and Rosén, Anders},
title = {Prevalence of EBV, HHV6, HCMV, HAdV, SARS-CoV-2, and Autoantibodies to Type I Interferon in Sputum from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients.},
journal = {Viruses},
year = {2025},
doi = {10.3390/v17030422},
note = {PubMed: 40143349},
url = {https://www.mecfsatlas.com/evidence/hannestad-2025-prevalence-ebv},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/hannestad-2025-prevalence-ebv
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