Today we delve into a fascinating study published in the Proceedings of the National Academy of Sciences (PNAS) that explores the long term effects of mild to moderate COVID infection on the brain, comparing between vaccinated and unvaccinated individuals a year after recovery. As our world continues to grapple with the COVID-19 pandemic and its complex biological legacy, understanding the potential neurological impacts of the virus is a crucial step forward. The PNAS study used advanced brain imaging to see the quantitative changes in patients’ brains; specifically, Magnetic Resonance Imaging (MRI) scans were conducted on the recovered individuals. Among all 11 MRI markers they tested — including white matter microstructure, cortical thickness, and white matter hyperintensity load — significant differences were found between the test and control group, particularly in regards to extracellular free water (an indication of brain matter changes) and mean diffusivity (a measure of a tissue’s microstructural integrity) . “Global measures of mean diffusivity (MD) and extracellular free water which were elevated in the white matter of post-SARS-CoV-2 individuals compared to matched controls”.
In addition to brain imaging, the study also used comprehensive neuropsychological assessments to map the long term impacts and contextualize the physical brain changes that were observed. The findings revealed subtle cognitive impairments in multiple domains, which included attention span, memory, and executive functions, although the study did not result in detecting extensive neuropsychological deficits in the post-SARS-CoV-2 individuals. Ultimately this case-control study discovered significant alterations of the cerebral white matter in non-vaccinated patients of COVID-19, however, these changes were not associated with poor cognitive functions during the first year after recovery. Further research is necessary to explore the link between brain alterations and clinical features of post-COVID individuals, but this research helped to emphasize the importance of seriously considering the potential long-term impacts on behavior of SARS-CoV-2 infections. As we transition into the post-pandemic world, we should be continuing to investigate the consequences of the COVID-19 pandemic on individuals’ well-being, even as a matter of public health policy.
References
Petersen, M., Nägele, F. L., & Mayer, C., et al. (2023). Brain imaging and neuropsychological assessment of individuals recovered from a mild to moderate SARS-CoV-2 infection (M. Behrmann, Ed.). PNAS. https://www.pnas.org/doi/10.1073/pnas.2217232120
Written by Anya Motwani.
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