Long-term symptom severity and clinical biomarkers in post-COVID-19/chronic fatigue syndrome: results from a prospective observational cohort.

Observed Findings

• Patients meeting ME/CFS diagnostic criteria (PCS-ME/CFS) maintained persistently high severity of most symptoms through 20 months post-infection, while broader PCS patients showed overall improvement
• Post-exertional malaise and fatigue remained present in both groups but were more pronounced in PCS-ME/CFS
• Lower hand grip strength at baseline correlated with symptom persistence, particularly in PCS-ME/CFS patients
• Inflammatory biomarkers decreased over time in both groups, but antinuclear antibodies did not normalize
• The study sub-classified 106 post-COVID patients, with a subset formally meeting ME/CFS diagnostic criteria

Inferred Conclusions

• Post-COVID syndrome can persist and manifest as ME/CFS beyond 20 months post-infection in a subset of patients with distinctly more severe disease courses
• Applying Canadian Consensus Criteria to classify post-COVID patients helps identify those with ME/CFS who require different clinical management strategies
• Baseline muscle strength may be a useful clinical indicator for predicting long-term symptom severity in post-COVID fatigue
• Biomarker profiles alone do not fully explain disease persistence; structural clinical classification improves prognostic understanding

Remaining Questions