Kouyoumdjian, Joao A, Yamamoto, Leticia A, Graca, Carla R · Cureus · 2025 · DOI
This study looked at how Long COVID and ME/CFS might be related by comparing people with Long COVID symptoms to those without and healthy controls. While many Long COVID patients experienced symptoms that overlap with ME/CFS—like post-exertional malaise (feeling worse after activity), brain fog, and sleep problems—only about 1 in 5 Long COVID patients actually met the official diagnostic criteria for ME/CFS. The findings suggest that Long COVID and ME/CFS are related but distinct conditions.
Understanding whether Long COVID and ME/CFS are the same condition or related-but-different diseases is crucial for developing appropriate treatments and diagnostic approaches. This study helps clarify that while Long COVID and ME/CFS share many symptoms, they may represent distinct conditions or disease subtypes, which could guide future research and clinical management strategies.
This small cross-sectional study cannot establish causality or determine whether Long COVID causes ME/CFS or whether they share common underlying mechanisms. The relatively low prevalence of ME/CFS diagnosis in all groups means the findings may not generalize to larger, more diverse populations, and the lack of significant differences in ME/CFS prevalence across groups limits conclusions about specific associations between Long COVID status and ME/CFS diagnosis.
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
Kouyoumdjian, Joao A, Yamamoto, Leticia A, & Graca, Carla R (2025). Exploration of Intersections and Divergences of Long COVID and Chronic Fatigue Syndrome.. Cureus. https://doi.org/10.7759/cureus.90607
BibTeX
@article{mecfsatlas-kouyoumdjian-2025-exploration-intersections,
author = {Kouyoumdjian, Joao A and Yamamoto, Leticia A and Graca, Carla R},
title = {Exploration of Intersections and Divergences of Long COVID and Chronic Fatigue Syndrome.},
journal = {Cureus},
year = {2025},
doi = {10.7759/cureus.90607},
note = {PubMed: 40978825},
url = {https://www.mecfsatlas.com/evidence/kouyoumdjian-2025-exploration-intersections},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/kouyoumdjian-2025-exploration-intersections
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