A Cross-Sectional Study of Symptom Prevalence, Frequency, Severity, and Impact of Long COVID in Scotland: Part I.
Mclaughlin, Marie, Cerexhe, Luke, Macdonald, Eilidh et al. · The American journal of medicine · 2025 · DOI
Quick Summary
Researchers surveyed 253 people living with long COVID in Scotland to understand which symptoms are most common and how severe they are. The most frequent symptoms were post-exertional malaise (when activity makes symptoms worse), extreme tiredness, and thinking problems. The study found that people living in areas with more deprivation experienced more symptoms, but factors like vaccination status and age did not significantly affect symptom patterns.
Why It Matters
This study provides crucial national-level data on long COVID symptom patterns in Scotland, filling a gap in UK-specific epidemiological knowledge. The identification of post-exertional malaise as nearly universal in this population strengthens the case for PEM-centered clinical assessment and validates patient-reported experiences, supporting advocacy for appropriate diagnostic criteria and management approaches.
Observed Findings
Post-exertional malaise was reported by 95% of participants, the highest symptom prevalence identified.
Fatigue and tiredness (85% prevalence) occurred most frequently among symptoms reported.
Sleep difficulties, activity limitations, and nausea emerged as the most severe symptoms when present.
Scottish Index of Multiple Deprivation showed significant association with increased symptom number, severity, and frequency.
Vaccine status, age, sex, and smoking status demonstrated limited or no significant association with symptom patterns.
Inferred Conclusions
Post-exertional malaise should be recognized as a near-universal feature of long COVID in this population, warranting centrality in clinical assessment and case definitions.
Socioeconomic deprivation correlates with greater symptom burden, suggesting potential barriers to recovery or differential health impacts by socioeconomic status.
Long COVID presents substantial functional impairment and requires longitudinal investigation to understand disease trajectory and societal impact.
Remaining Questions
What mechanisms explain the strong association between deprivation and symptom severity—is this socioeconomic stress, healthcare access barriers, or biological factors?
What This Study Does Not Prove
This cross-sectional study cannot establish causation or determine whether observed associations (e.g., deprivation and symptom severity) reflect direct causal mechanisms or confounding factors. The self-selected survey sample may not be fully representative of all people with long COVID in Scotland, and the exclusion of hospitalized patients limits generalizability to the full spectrum of post-COVID illness.
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 →
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