Legler, Franziska, Meyer-Arndt, Lil, Mödl, Lukas et al. · EClinicalMedicine · 2023 · DOI
This study followed 106 people with long-term fatigue after COVID-19 for up to 20 months to see how they recovered over time. Researchers found that some patients met the diagnostic criteria for ME/CFS and had persistent, severe symptoms including fatigue and post-exertional malaise (worsening after activity), while others improved more substantially. Lower muscle strength at the start of illness was linked to ongoing symptoms, especially in those with ME/CFS.
This study provides evidence that ME/CFS is a distinct subgroup within post-COVID illness with a different disease trajectory and persistent severity, supporting the use of diagnostic criteria to identify patients who need specialized monitoring and management. The findings validate ME/CFS diagnostic criteria in a post-COVID context and highlight that some post-COVID patients develop genuine ME/CFS rather than simply experiencing prolonged recovery.
This study does not establish that reduced grip strength or any biomarker *causes* symptom persistence—only that they are correlated. The study also does not explain the biological mechanisms underlying ME/CFS or why some post-COVID patients develop ME/CFS while others recover. Additionally, findings in this German cohort may not generalize to other populations or disease variants.
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
Legler, Franziska, Meyer-Arndt, Lil, Mödl, Lukas, Kedor, Claudia, Freitag, Helma, Stein, Elisa, et al. (2023). Long-term symptom severity and clinical biomarkers in post-COVID-19/chronic fatigue syndrome: results from a prospective observational cohort.. EClinicalMedicine. https://doi.org/10.1016/j.eclinm.2023.102146
BibTeX
@article{mecfsatlas-legler-2023-long-term,
author = {Legler, Franziska and Meyer-Arndt, Lil and Mödl, Lukas and Kedor, Claudia and Freitag, Helma and Stein, Elisa and Hoppmann, Uta and Rust, Rebekka and Wittke, Kirsten and Siebert, Nadja and Behrens, Janina and Thiel, Andreas and Konietschke, Frank and Paul, Friedemann and Scheibenbogen, Carmen and Bellmann-Strobl, Judith},
title = {Long-term symptom severity and clinical biomarkers in post-COVID-19/chronic fatigue syndrome: results from a prospective observational cohort.},
journal = {EClinicalMedicine},
year = {2023},
doi = {10.1016/j.eclinm.2023.102146},
note = {PubMed: 37662515},
url = {https://www.mecfsatlas.com/evidence/legler-2023-long-term},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/legler-2023-long-term
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