Even mild COVID-19 can lead to substantial brain changes

Magnetic resonance imaging (MRI) scans from before and after the COVID-19 diagnosis show adverse brain changes. In a new study from the U.K. Biobank, two magnetic resonance imaging (MRI) scans and cognitive testing were performed on people as part of a longitudinal population study predated the COVID-19 pandemic.

In 401 people, positive tests for SARS-CoV-2 occurred between the two MRIs (during the first 18 months of the pandemic); second MRI scans were performed an average of 141 days after positive SARS-CoV-2 tests in this group.

Compared with controls, people with COVID-19 had more reduction in grey matter thickness in the orbitofrontal cortex and parahippocampal gyrus, more tissue damage in regions connected to the olfactory cortex, and greater reduction in global brain size, and greater cognitive decline. Similar changes were not seen in a small group of participants who had developed non-COVID pneumonias between their two scans.

This study, combined with recent studies of SARS-CoV-2 infection of primates, provides strong evidence that even mild COVID-19 can be associated with brain changes.