12/20/2025
New research published today, December 19, 2025, is adding weight to something our community has known for a long time.
A large genetic analysis found meaningful overlap between genes associated with ME/CFS and genes previously linked to long COVID. The overlap was much higher than expected by chance.
What the study found:
• Thousands of small genetic variations linked to ME/CFS risk
• Strong signals in immune, nervous system, and stress-response pathways
• Dozens of genes overlapping with long COVID findings from other studies
What this suggests:
• Long COVID and ME/CFS likely share underlying biological mechanisms
• Post-viral illness is not random or psychological
• Genetics may help explain why some people develop long-term illness after infection and others do not
Important context:
• This study is a preprint and has not yet been peer reviewed
• Genetic association does not mean cause
• Findings need replication and follow-up studies
Why this still matters:
Preprint or not, this work aligns with a growing body of research pointing to immune and neurological dysfunction in post-viral illness. It strengthens the scientific foundation already being built and pushes the conversation further away from dismissal and toward mechanism, measurement, and care.
A major new genetic study suggests that myalgic encephalomyelitis, also known as ME or chronic fatigue syndrome, is driven by thousands of small genetic factors working together rather than a single cause. The findings also show a significant overlap with long COVID, strengthening the case that both...