Researchers have discovered that during the first months of coronavirus infection, even COVID-19 cases with mild symptoms have been found to be associated with some tissue damage in the brain. And regions of the brain associated with the sense of smell have been found to have accelerated losses.

A British study led by researchers at the University of Oxford also found that COVID-19 infections are associated with cognitive function deficits. The study used brain scans taken before and after participants in the study contracted the coronavirus.

Gwenaëlle Douaud, the lead author on the paper and an associate professor at the Nuffield Department of Clinical Neurosciences at Oxford said, “It is brain damage, but it is possible that it is reversible.” She said, "it is still relatively scary because it was in mildly infected people,” NBC reported.

“The brain is plastic, which means it can reorganize and heal itself,” she said. “This is true even in older people.”

The research was published on Monday in the journal Nature and found that, among those who had COVID-19, those individuals experienced a greater loss of gray matter in the brain and had a higher rate of abnormalities in the brain.

Researchers used data and brain scans that were compared to that of the UK Biobank, which is considered to be a control group of participants who had not tested positive for COVID-19. Those in that group were matched to the COVID-19 positive group according to things like blood pressure, smoking, diabetes, socioeconomic status, and obesity.