Carter et al. (2026)
- Authors: Isabelle V. Carter, Anna May, Isabella C. Hsieh, Juliane Torer, David Rosenberg, Kingman P. Strohl
- Institutes: Department of Psychiatry, Robert Wood Johnson University Hospital, New Brunswick, NJ, USA, Case Western Reserve University, Cleveland, OH, USA
- Publisher: Sleep and Breathing (Springer)
- Link: DOI
Summary
This study clarifies that Long COVID fatigue is a diverse spectrum rather than a single condition, with only a small minority of patients meeting formal ME/CFS diagnostic criteria. This distinction is crucial because treating all post-COVID fatigue as ME/CFS could lead to ineffective clinical trials and misaligned treatment strategies. By highlighting that brain fog is a separate but overlapping feature, the research helps clinicians better categorize patient symptoms. Ultimately, these findings advocate for more nuanced diagnostic frameworks to improve care for those suffering from post-viral exhaustion.
What was researched?
This study investigated the different presentations of fatigue in a Long COVID clinic cohort and compared them against the formal 2015 CDC diagnostic criteria for ME/CFS.
Why was it researched?
While fatigue is the most common symptom of Long COVID, it remains unclear how often it mirrors ME/CFS and how it interacts with other symptoms like brain fog and psychiatric health.
How was it researched?
Researchers performed a retrospective analysis of 277 patients evaluated at a referral clinic an average of 10 months post-infection. They used standardized measures including the Fatigue Severity Score, PHQ-9 for depression, and specific criteria for ME/CFS to categorize the participants.
What has been found?
The researchers found that while 73.5% of the cohort reported primary fatigue, only 21.9% of those fatigued patients actually met the criteria for ME/CFS. Brain fog was a prevalent feature in 51.9% of patients but appeared to be a distinct symptom that did not overlap perfectly with fatigue. Anxiety and previous psychiatric diagnoses were significantly more common in patients who met the ME/CFS criteria than in those who did not.
Discussion
The findings suggest that the majority of Long COVID fatigue cases represent a broader spectrum that does not fit the traditional ME/CFS phenotype. This heterogeneity could confound clinical trials if participants are not carefully screened and subgrouped based on their specific symptom profiles.
Conclusion & Future Work
Post-COVID fatigue should be managed as a broad spectrum of conditions. Future research and clinical trials must distinguish between ME/CFS-like fatigue and other fatigue phenotypes to ensure treatments are correctly targeted.