Study Finds Why Some Covid Patients Never Recover Sense of Smell

Why can’t some people smell things months after having Covid? Researchers have been working to find out why some people struggle to regain their sense of smell post-Covid. 

Scientists are saying that the reason could be the immune response of the individual. 

Researchers found that people who do not smell again after covid have evidence of continued inflammation and an immune response that continued to persist after the virus was long gone.

For some, Covid knocked out their sense of smell for months with no precise scientific explanation of why and no therapeutic drugs specifically designed to restore it. Millions around the world lost their sense of smell for at least six months after Covid. 

A research group led by Duke Health could be nearing some answers.

The researchers took biopsies deep inside the nasal cavities of patients struggling to regain their smell months after coming down with Covid. They found evidence of continued inflammation and an immune response that persisted after the virus was long gone, according to a small study published Wednesday in the journal Science Translational Medicine. 

This new research could help develop drugs specifically to address the problem in the toughest cases, and it also could help scientists better understand how long Covid affects other organ systems.

The study evaluated biopsied tissue from the olfactory linings of 24 people, including nine who lost their smell for at least four months. 

This biopsy revealed an interesting finding regarding T cells.

T cells are the immune system’s “long-term memory. They are a specific type of immune cell that essentially finds and kills infected cells and pathogens. 

The researchers found that the T cells are seemingly engaged in an autoimmune-like response in the nose, with the cells being inflamed in the part of the nose where the nerve cells for cells are located, the olfactory epithelium.

Because the area has delicate tissue, whatever response is happening with the T cells causes damage. This may mean nerve cells decline, therefore imparting the senses of smell.