Assessing the Relationship in Symptomology of Myalgic Encephalitis/Chronic Fatigue Syndrome and Long COVID.
Garapaty, Nikitha, Reyes, Kristina M, Tehrani, Lily et al. · American journal of medicine open · 2025 · DOI
Quick Summary
This study compared symptoms in people with ME/CFS, Long COVID, both conditions together, and people without either condition. Researchers found that people who have both ME/CFS and Long COVID experience the worst symptoms—including memory problems, anxiety, depression, fatigue, and difficulty exercising—compared to people with just one condition or neither. The findings suggest these two illnesses may interact in ways that make symptoms more severe when they occur together.
Why It Matters
This research is important because it highlights that ME/CFS and Long COVID may not be independent conditions—patients who have both may face compounded symptom burden. Understanding this potential interaction could help clinicians better recognize and treat patients experiencing both illnesses simultaneously, and may guide future research into shared biological mechanisms between these conditions.
Observed Findings
People with both ME/CFS and LC reported the highest rates of memory issues, anxiety, depression, fatigue, and physical activity limitations.
People with only ME/CFS reported more of these symptoms than those with only Long COVID.
The difference in symptom severity between groups remained statistically significant even after controlling for sex, race/ethnicity, age, life satisfaction, insurance coverage, poverty ratio, and other illnesses.
All four symptom categories (anxiety, depression, fatigue, physical activity difficulty) showed the same pattern across groups.
Inferred Conclusions
ME/CFS and Long COVID may interact synergistically rather than additively—meaning their combined effect is greater than the sum of separate effects.
Shared or overlapping pathophysiological mechanisms may underlie both conditions and could explain their similar symptom profiles.
Clinical assessment and treatment approaches should account for the possibility that patients may have both conditions simultaneously.
Remaining Questions
What are the specific shared or overlapping biological mechanisms between ME/CFS and Long COVID that might explain this synergistic effect?
Does having one condition increase the risk of developing the other, or do they arise independently from different triggers?
What This Study Does Not Prove
This study does not prove that ME/CFS and Long COVID share the same underlying cause, nor does it establish whether one condition increases risk of developing the other. The cross-sectional design captures associations at a single point in time, so it cannot determine causation or the temporal sequence of symptom development. Survey-based diagnoses were not confirmed by clinical evaluation, which may limit diagnostic accuracy.