Clinical Characteristics of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Diagnosed in Patients with Long COVID.
Tokumasu, Kazuki, Honda, Hiroyuki, Sunada, Naruhiko et al. · Medicina (Kaunas, Lithuania) · 2022 · DOI
Quick Summary
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.
Why It Matters
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.
Observed Findings
- ME/CFS prevalence in long COVID patients was 16.8% using standardized diagnostic criteria
- Post-exertional malaise and general fatigue occurred in 89.4% of ME/CFS cases
- Equal male-to-female ratio (48.9% male, 51.1% female), contrasting with typical ME/CFS epidemiology
- Characteristic associated symptoms: dizziness (frequency not specified), chest pain, insomnia (23.4%), and headache (34.0%)
- Patients with ME/CFS showed more severe acute-phase COVID-19 compared to those without ME/CFS
Inferred Conclusions
- Severe acute COVID-19 infection may be a risk factor for subsequent ME/CFS development
- Post-exertional malaise is a nearly universal feature of ME/CFS in long COVID populations
- The absence of typical female predominance in this cohort suggests possible unique features of post-COVID ME/CFS compared to idiopathic ME/CFS
Remaining Questions
- What are the biological mechanisms linking acute COVID-19 severity to ME/CFS development?
- Why does this long COVID cohort show equal sex distribution when ME/CFS typically affects more women?
- How do long COVID-associated ME/CFS outcomes and treatment responses compare to idiopathic ME/CFS?
- Can early clinical markers of severe acute infection predict which long COVID patients will develop ME/CFS?
What This Study Does Not Prove
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.
Topics
Tags
Metadata
- DOI
- 10.3390/medicina58070850
- PMID
- 35888568
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 7 April 2026