Why do Covid-19 patients have symptoms of loss of smell?

One of the most curious as well as annoying, even life-changing symptoms is the loss of smell. Scientists from Johns Hopkins School of Medicine (USA) have come up with an explanation.

Dr. Cheng-Ying Ho, a neurologist at Johns Hopkins School of Medicine, said: “This is not a phenomenon that occurs commonly in other respiratory diseases. We decided to delve deeper into the mechanism of smell to see what really happens at the cellular level when SARS-CoV-2 enters the body.”

The findings explain some of the underlying reasons and provide insight into what is going on during Covid-19 infection in other organs, including the brain.

They were not surprised to find inflammation in the olfactory bulb (the area that transmits odor signals to the brain) of people infected with the SARS-CoV-2 virus. Researchers have noted Covid-19 seems to cause inflammation around the body.

Damaged neurons result in little or no notification to the brain about odors.

However, the researchers were surprised to find no SARS-CoV-2 virus in the olfactory bulb. That seems to confirm that the trouble with the smell is not a direct result of a viral infection, but a secondary issue.

Dr Ho said they still don’t know which Covid-19 patients are most likely to lose their sense of smell and how bad the reaction will be. In a study published last week in the journal JAMA Neurology, the loss of smell was not associated with the severity of the Covid-19 infection.

“In our study, the patient with the most severe olfactory impairment had only scurvy, meaning no difficulty breathing and no mechanical ventilation,” said Dr. Ho.

Most people regain their sense of smell after 3 or 4 weeks, with only a small percentage still having it after 6 months.

An Yen (According to Baltimore Sun)