C57-20 Preserved Structural Integrity on Brain Imaging After Covid-19 Vaccination and SARS-CoV-2 Infection: Data From the C4R Study

Rationale

The impacts of COVID-19 vaccination and SAR-CoV-2 infection on brain tissues and structures remain controversial. This study examines whether COVID-19-related exposures are associated with measurable changes in structural magnetic resonance imaging (MRI) using data from the US general population-based Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study.

Methods

The C4R study is an observational meta-cohort study of 14 NIH-funded population-based cohorts, with directly measured data on COVID-19-related exposures, including vaccination and infection. For this analysis, we included participants with C4R data and paired brain MRI scans from both before and after the onset of the COVID-19 pandemic (defined as March 1, 2020) from two cohorts: the Atherosclerosis Risk in Communities study (ARIC) and Framingham Heart Study (FHS). MRI features examined as outcomes were white matter volume (WMV), gray matter volume (GMV), total brain volume (BV), hippocampal volume (HV), and white matter hyperintensity volume (WMH), a marker of microvascular disease. Exposures included SARS-CoV-2 infections identified via questionnaires, serosurveys, and medical record reviews from 2020-2025. Infections resulting in hospitalization were classified as severe. Time-to-recovery, symptoms of long COVID, and vaccination status were self-reported by questionnaire. Analysis of covariance (ANCOVA) estimated associations between COVID-19-related exposures and pandemic MRI-measured outcomes, with adjustment for: the corresponding pre-pandemic MRI measure, the time between the two MRI scans, age, sex, systolic blood pressure, diabetes, and cardiovascular disease.

Results

Of 270 participants with available data, mean (SD) age was 80.6 years (10.6); 43.0% were male; and the mean (SD) interval between paired MRI scans was 4.2 (2.0) years. Most (90%) were vaccinated (of whom 6.7% vaccinated before infection) and 7.9% reported SARS-CoV-2 infection (of which 13.6% were severe infections) prior to their pandemic MRI (conducted March 2020 - June 2022). In fully adjusted models, there was no statistically significant association for change in WMV, GMV, BV, HV, or WMH with SAR-CoV2 infection status, infection severity, vaccination status, or vaccination timing (Table, P > 0.05 for all comparisons). Self-reported symptoms of long COVID and vaccine manufacturer were also not associated with MRI outcomes.

Conclusions

Based on repeated (pre-pandemic and pandemic era) structural MRI scans, we found no evidence that SARS-CoV-2 infection or COVID-19 vaccination were associated with changes in brain structure or brain microvascular disease. These findings are consistent with prior data supporting COVID-19 vaccine safety and suggest resilience of brain structures following SARS-CoV-2 exposures. Nonetheless, further research is warranted using more sensitive measures and assessing longer term effects.

This abstract is funded by: OT2HL156812