Last Updated: Dec 30, 2022

Millions of people who suffered from the loss of sense of smell after being diagnosed with COVID-19 might not be able to regain it ever again. A group of health experts has said that it might be due to an ongoing unusual immune response that rescinds cells in the nose. A new study has shown that a declining number of olfactory nerve cells in the nose might be the cause of the absolute loss of smell among such patients.

The findings of the new study highlight an ongoing sensory consequence caused by the global COVID-19 crisis. The authors of the study have analyzed nasal tissue extracted from COVID-19 patients. They have discovered that patients having long-term issues with their sense of smell have been found with inflammation-driving immune cells that are inside the delicate nasal lining that have wiped out crucial sensory nerve cells.

An associate professor of neurobiology from Duke University in North Carolina, Dr. Bradley Goldstein has said tissue from the layer of the nose has contained exclusive immune cells generating inflammatory signs, blended with fewer olfactory nerve cells. This rare immune reaction has been observed only in patients who have been dealing with a loss of smell persisting for months.

Dr. Bradley Goldstein has said that it seems that there is an unsettled local immune reaction, which the delicate olfactory cells are dealing with currently. Ever since health professionals have reported that many COVID-19 patients have lost their sense of smell, it has been uncertain if the virus harms sensory cells in the nose, areas of the brain that process olfactory info, or both.

The authors of the study have observed biopsied tissue from the nasal lining of around 24 COVID-19 patients, and nine COVID-19 patients who have been dealing with a lost sense of smell for at least four months. Tissue extracted from the last group of participants showed that T-cells involved in inflammation penetrated the nasal lining where smell nerve cells are usually found. The rare immune reaction was seen despite the patients having no visible thread of the SARS-CoV-2 virus. It shows that the rare immune reaction has been continuing even after the recovery from COVID-19 infection.

Health experts have also looked at the count of sensory nerve cells that are responsible for the sense of smell. They have said that COVID-19 patients who have dealt with long-term loss of smell had notably less sensory nerve cells. It might be due to the delicate tissue of the nasal lining has been dented by the T-cell-driven inflammation

The lead author of the study has claimed that at least 5% of people who deal with a damaged sense of smell during a COVID infection might not be able to regain their sense of smell faster or fully. As per the data, around about 15 million people across the globe who are dealing with COVID-19 infection or have recovered from a COVID infection have not been able to fully regain their sense of smell.

Health experts who have been involved in the new study have said that at present, there is no effective treatment available to treat this disorder. The authors of the study have claimed that the new findings might help find a new treatment for loss of smell that takes place post-COVID recovery. The findings suggest that blocking inflammation-driving immune cells nearby in the nasal lining might be a solution to it.  This study has been put together by health experts from Duke Health.

The findings of the study have been released in an academic journal known as Science Translational Medicine. A neuroscientist from the University of Oxford, Dr. Gwenaelle Douaud, who has evaluated the effects of COVID-19 infection on the brain has said that among COVID-19 patients, stubborn olfactory issues have been exposed to be linked to the reduction of brain regions related to the sense of smell.