Does mRNA-based COVID-19 vaccination in the subacute phase lead to microstructural brain changes? A prospective pilot...

Area of Science:

• Neurology
• Radiology
• Vaccinology

Background:

• Messenger ribonucleic acid (mRNA)-based vaccines delivered via lipid nanoparticles (LNP) were crucial for managing the SARS-CoV-2 pandemic.
• Concerns exist regarding rare neurological complications and potential structural cerebral changes following vaccination.

Purpose of the Study:

• To test the hypothesis that LNP-mRNA-based SARS-CoV-2 vaccination does not induce significant microstructural cerebral changes in healthy adults.
• To evaluate potential changes in white matter hyperintensities (WMH) and microstructural integrity of gray and white matter.

Main Methods:

• Prospective pilot study involving 3 Tesla brain MRI scans at three time points (pre-vaccination, 1-2 weeks post-dose 2, 2-3 months post-dose 2).
• Analysis included T2-weighted FLAIR, synthetic 3D T1-weighted MGRE, and 3D quantitative T1 mapping (qT1).
• WMH were assessed visually (Prins scale) and semiquantitatively; microstructural changes evaluated using qT1 values.

Main Results:

• No new or progressive white matter hyperintensities (WMH) were observed in any participant.
• No significant intraindividual qT1 changes were detected, with deviations within scan-rescan variability limits.
• Apart from a minor decrease in one preexisting WMH, no visually detectable structural brain alterations were found.

Conclusions:

• Findings provide no evidence for white matter hyperintensity progression after LNP-mRNA-based SARS-CoV-2 vaccination.
• No microstructural cerebral changes were detected in healthy adults in the subacute phase post-vaccination.
• The study supports the safety of LNP-mRNA COVID-19 vaccines concerning structural brain integrity.