Scientists used special brain scans to look at people who still feel sick after COVID‑19. They expected to see a lot of inflammation, but they did not.
The research was done at the University of Turku in Finland. Fourteen people with long COVID, eleven healthy volunteers, and thirteen patients with multiple sclerosis (MS) took part.
All participants had PET scans that can spot inflammation and MRI scans that show brain structure. Blood tests were also done to check for signs of nerve damage.
Compared with the MS group, the long COVID group showed far less inflammation in the brain’s white matter. There were also no important differences between long COVID patients and healthy volunteers in blood markers for inflammation or brain cell loss.
People who were scanned within a year after infection showed a little more white‑matter activity than those who were scanned later. This suggests that any brain inflammation might be stronger early on and then fade.
Another clear pattern appeared: participants who felt more anxious, depressed, or had a lower quality of life showed extra activity in the hippocampus and amygdala. These areas help with memory, emotions, and stress responses.
The findings hint that the brain’s emotional centers may play a big role in how severe long COVID symptoms become, rather than widespread inflammation alone.
These results could change how doctors treat long COVID. Instead of only trying to reduce inflammation, some patients might benefit from stress‑relief techniques and emotional‑health support.
The study was published in the Journal of Neurology and is part of the InFLAMES Flagship program, a partnership between the University of Turku and Åbo Akademi University.