corona virus-Covid19

COVID-19 Damages Brain Region That Affects Smell Interview with:

Cheng-Ying Ho, MD, PhD Associate Professor  Department of Pathology Johns Hopkins University School of Medicine

Dr. Cheng-Ying Ho

Cheng-Ying Ho, MD, PhD
Associate Professor
Department of Pathology
Johns Hopkins University School of Medicine  What is the background for this study? 

Response: Smell loss is one of the most common symptoms of COVID-19 infection. The mechanism of COVID-19-related smell loss is unclear. Previous studies mainly focused on the effect of the viral infection on the lining of the nasal cavity. We went a step beyond to examine the olfactory bulb, a region that transmits smell-related signals to the brain.  What are the main findings?

Response: We collected olfactory bulb from 23 diseased patients with COVID-19 along with 14 deceased individuals negative for COVID-19. We found damages of olfactory axons (nerve processes) and small vessels in COVID-19 patients. COVID-19 patients with smell loss had even more severe nerve and vascular damage in the olfactory region than those without smell loss. The damage is not caused by viral infection of the olfactory nerve cells and most likely a consequence of inflammation related to the infection. What should readers take away from your report?

Response: COVID-19 not only affects smell function by infecting the cells lining the nasal cavity, but also causes significant damage in the brain region that controls smell. What recommendations do you have for future research as a result of this work?

Response: If inflammation is indeed the main mechanism of olfactory tissue damage, it will be important to know if vaccination can reduce the inflammation as well as the damage in the olfactory region. It may also be feasible to explore the possibility of using anti-inflammatory drugs to treat COVID-19-related smell loss. Is there anything else you would like to add?

Response: I would like to add that this study is the first study to demonstrate COVID-19-related injuries at a super-high resolution in the olfactory bulb, a region that transmits smell-related signals to the brain. It is also the first study to confirm the pathology in COVID-19 patients with smell loss.

I have no disclosure


Ho C, Salimian M, Hegert J, et al. Postmortem Assessment of Olfactory Tissue Degeneration and Microvasculopathy in Patients With COVID-19. JAMA Neurol. Published online April 11, 2022. doi:10.1001/jamaneurol.2022.0154

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Last Updated on April 13, 2022 by Marie Benz MD FAAD