The results of this new study, ‘Varying Levels of Inflammatory Activity in Brain and Body of Patients with Persistent Fatigue and Difficulty Concentrating After COVID-19: A TSPO PET Study‘, adds further support to the hypothesis that low level neurological inflammation, caused by the immune response to the initial infection, is involved in Long Covid.
The Journal of Nuclear Medicine, September 2025
Summary
- The researchers used a PET scan marker that detects neuroinflammation by binding to TSPO, a protein linked to activated brain immune cells (microglia).
- Some participants with symptoms showed higher brain inflammation signals compared to those without symptoms. No consistent differences were found in the rest of the body.
- However, the results varied widely between individuals, and the brain and body inflammation levels were not linked to how severe symptoms were.
Extracts
“A significant number of patients report persistent fatigue and difficulty concentrating after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a condition known as post–coronavirus disease 2019 (post-COVID) syndrome. The underlying mechanisms for these complaints remain poorly understood.”
“Increased specific [18F]DPA-714 binding was found in some individuals with post-COVID syndrome, indicating the presence of an inflammatory subtype and further supporting the role of neuroinflammation in subtypes of post-COVID syndrome.”
MEA Comment
What causes cognitive dysfunction/brain fog in Long Covid – and possibly in ME/CFS?
This is an interesting new study using nuclear medicine imaging.
The results add further support the hypothesis that low level neurological inflammation, caused by the immune response to the initial infection, is involved.
Dr Charles Shepherd,
Trustee and Hon. Medical Adviser to the ME Association,
Member of the 2018-2021 NICE guideline on ME/CFS committee,
Member of the 2002 Chief Medical Officer's Working Group on ME/CFS
