[Creative Cultivation Program] Why do people lose their sense of smell after being infected with COVID-19?

As a COVID-19 patient, after I was infected with the coronavirus and recovered, I felt a loss of smell. I couldn't smell many things, and nothing tasted good. After doing a test in my private circle of friends, I found that I was not the only one with a problem with my sense of smell. Does COVID-19 really cause a loss of smell?

In December 2022, a group of scientists from Duke University Medical Center in the United States stated that one of the symptoms commonly associated with COVID-19 infection is loss of smell. Many people who experience changes in their sense of smell during the acute phase of viral infection will recover within one to two weeks afterwards, but some will not. The reason for the failure to recover the sense of smell after COVID-19 infection is related to the continued immune attack on olfactory nerve cells and the reduction in the number of related cells.

There is a very special mucous membrane in the upper part of our nose, called the "olfactory epithelium", which can detect odor molecules and quickly transmit signals to the brain through neurons, producing happy or uncomfortable reactions.

If this signaling pathway is disrupted due to other reasons, it may lead to loss of smell or abnormality. The new coronavirus has a strong adsorption ability to the olfactory epithelium, and the new coronavirus can use the ACE2 receptor protein to invade cells. Once the virus invades, the immune response will be initiated, causing inflammation of the olfactory epithelium. The original purpose of the immune response is to kill the virus, but it was unexpectedly too strong, causing the olfactory neurons to lose cilia. Without cilia, it is difficult for olfactory neurons to capture odor molecules, so we feel a loss of smell, but don't worry, scientists say that olfactory neurons have a certain ability to repair, and we have to wait until the inflammation subsides, new cilia will grow out, and the sense of smell will recover.

However, different people recover at different times, and even during the recovery process, their sense of smell may be confused. Some foreign COVID-19 patients said, "The chicken pasta tastes like dishwashing liquid," while others said, "The delicious milk coffee and toast breakfast now smells like a field with fertilizer." If you smell some strange odors in a short period of time, you might as well change your mindset. After all, you can taste different flavors in the same food, and such an opportunity is not always available.