Carter, Isabelle V, May, Anna, Hsieh, Isabella C et al. · Sleep & breathing = Schlaf & Atmung · 2026 · DOI
This study looked at 277 people with long COVID who visited a specialized clinic, focusing on those experiencing fatigue. About 73% reported fatigue as a main symptom, but only about 22% of those met the strict ME/CFS diagnostic criteria. The researchers found that fatigue severity varied widely, and fatigue often came alongside other symptoms like brain fog, anxiety, and reduced physical functioning.
This study demonstrates that post-COVID fatigue presents as a heterogeneous spectrum rather than a single condition, with only about 1 in 5 fatigued patients meeting ME/CFS criteria. Understanding this diversity is crucial for researchers designing clinical trials and for clinicians tailoring treatment approaches to individual patients rather than applying one-size-fits-all protocols.
This study does not establish causality between COVID-19 and fatigue spectrum presentations, nor does it determine whether post-COVID fatigue is mechanistically distinct from ME/CFS or other fatigue disorders. The referral clinic sample may not represent the broader long COVID population, potentially overrepresenting more severe cases. Cross-sectional design prevents determination of whether psychiatric symptoms precede or follow fatigue onset.
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
Carter, Isabelle V, May, Anna, Hsieh, Isabella C, Torer, Juliane, Rosenberg, David, & Strohl, Kingman P (2026). The fatigue spectrum in a community-based long haul COVID cohort.. Sleep & breathing = Schlaf & Atmung. https://doi.org/10.1007/s11325-025-03512-y
BibTeX
@article{mecfsatlas-carter-2026-fatigue-spectrum,
author = {Carter, Isabelle V and May, Anna and Hsieh, Isabella C and Torer, Juliane and Rosenberg, David and Strohl, Kingman P},
title = {The fatigue spectrum in a community-based long haul COVID cohort.},
journal = {Sleep & breathing = Schlaf & Atmung},
year = {2026},
doi = {10.1007/s11325-025-03512-y},
note = {PubMed: 41620575},
url = {https://www.mecfsatlas.com/evidence/carter-2026-fatigue-spectrum},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/carter-2026-fatigue-spectrum
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