According to a new study, published in the journal Nature, contracting COVID-19 infection may cause changes to the brain.

Researchers noted significant differences in magnetic resonance imaging (MRI) scans prior to and after the infection. They noted that even after mild infection, the overall brain size had shrunk slightly, with lesser grey matter in the parts of the brain associated with smell and memory.

The UK Biobank project has followed the health status of 500,000 individuals for about 15 years and has a database of scans from before the pandemic. Therefore, the researchers could look at the long-term health effects of coronavirus. They subjected 401 participants to rescanning about 4.5 months, on average, after the infection. Around 96% of them had had mild illness. They also rescanned 384 participants who did not contract the infection. The overall brain size was found to shrink by about 0.2% to 2% in infected participants. They noted losses in grey matter in the olfactory areas and regions tied to memory. People who had recently recovered from COVID-19 found it a little difficult to perform complex mental tasks.

However, the researchers do not know if the changes are permanent or reversible… (BBC, March 7, 2022)