Publications

Pathology Evidence Sheds New Light on Loss of Smell in COVID-19

Loss of smell is an early and common presentation of COVID-19 infection. To determine the mechanism of COVID-19-associated smell dysfunction, Dr. Ho and her team collected olfactory bulb tissue from deceased COVID-19 and control patients. Olfactory bulb is a region of the brain that serves as the hub to receive and relay information regarding scents. Dr. Ho and her team observed more damage in axons (nerve processes) and small vessels in olfactory bulb of COVID-19 patients than that of control individuals. The damage is most severe in COVID-19 patients that had experienced loss of smell. The extreme damage in some COVID-19 patients may explain why the sense of smell is permanently lost even after the patients recover from the infection. The team did not detect the virus in olfactory bulb from the majority of the COVID-19 patients. Instead, they think that inflammation, rather than the damage directly from the virus, causes loss of smell.