Blood-brain barrier damage
Leakage of the blood-brain barrier, measurable in brain-fog patients — but with no targeted treatment yet.
Imaging work (DCE-MRI) has shown measurable blood-brain-barrier leakage specifically in patients with brain fog, alongside sustained systemic inflammation — making this a real, measurable phenomenon rather than a metaphor. However, there is no proven BBB-targeted therapy; approaches are experimental or borrowed from the immune and microclot toolkits, and 'BBB repair supplements' are unproven. Candidate blood biomarkers (GFAP, neurofilament light) are under study but not yet clinically validated for Long COVID.
How it's tested
DCE-MRI (blood-brain barrier integrity)
Dynamic contrast-enhanced MRI quantifies contrast leakage across the blood-brain barrier. Research-grade.
Neuro blood biomarkers (GFAP, NfL)
Blood markers of glial activation and neuronal injury, under study as cheaper proxies for brain involvement. Not yet validated for Long COVID.