News Health & Medicine Long COVID brain fog may be due to damaged blood vessels in the brain The result suggests there is a biological basis for this symptom Brain fog is a debilitating symptom commonly reported by people with long COVID. Now, scientists have linked the symptom to leaky boundaries in the brain. baona/iStock/Getty Images Plus Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Meghan Rosen March 15, 2024 at 8:30 am Leakiness in the brain could explain the memory and concentration problems linked to long COVID. In patients with brain fog, MRI scans revealed signs of damaged blood vessels in their brains, researchers reported February 22 in Nature Neuroscience.