Tokumasu, Kazuki, Honda, Hiroyuki, Sunada, Naruhiko et al. · Medicina (Kaunas, Lithuania) · 2022 · DOI
This study examined patients with long COVID who developed ME/CFS, a serious condition causing extreme fatigue and worsening after activity. Researchers found that about 17% of long COVID patients met standardized medical criteria for ME/CFS, with fatigue and post-exertional malaise being the most common symptoms. Interestingly, men and women were affected equally in this group, which differs from typical ME/CFS patterns.
This study provides rare rigorous data on ME/CFS diagnosed using standardized clinical criteria in long COVID patients, rather than relying on patient-reported symptoms alone. Understanding ME/CFS prevalence and specific symptom profiles in post-COVID populations helps clinicians recognize this serious condition earlier and supports research into shared pathophysiological mechanisms between viral infections and ME/CFS.
This study does not establish causality between COVID-19 severity and ME/CFS development—it only observes correlation. The retrospective design cannot determine whether acute infection severity directly causes ME/CFS or if other unmeasured factors contribute. Findings from a single Japanese clinic may not generalize to other populations or healthcare systems.
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
Tokumasu, Kazuki, Honda, Hiroyuki, Sunada, Naruhiko, Sakurada, Yasue, Matsuda, Yui, Yamamoto, Koichiro, et al. (2022). Clinical Characteristics of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Diagnosed in Patients with Long COVID.. Medicina (Kaunas, Lithuania). https://doi.org/10.3390/medicina58070850
BibTeX
@article{mecfsatlas-tokumasu-2022-clinical-characteristics,
author = {Tokumasu, Kazuki and Honda, Hiroyuki and Sunada, Naruhiko and Sakurada, Yasue and Matsuda, Yui and Yamamoto, Koichiro and Nakano, Yasuhiro and Hasegawa, Toru and Yamamoto, Yukichika and Otsuka, Yuki and Hagiya, Hideharu and Kataoka, Hitomi and Ueda, Keigo and Otsuka, Fumio},
title = {Clinical Characteristics of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Diagnosed in Patients with Long COVID.},
journal = {Medicina (Kaunas, Lithuania)},
year = {2022},
doi = {10.3390/medicina58070850},
note = {PubMed: 35888568},
url = {https://www.mecfsatlas.com/evidence/tokumasu-2022-clinical-characteristics},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/tokumasu-2022-clinical-characteristics
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