Why many do not recover their sense of smell after Covid-19: a study discovered the cause

The Covid-19 leaves some sequelae in the body of the people who endured the disease and one of the most common is lack of smell or taste after being discharged. In that sense, a study discovered why this situation can last up to years after being diagnosed.

Is about research published in the scientific journal Science Translational Medicine that tries to explain the causes of “anosmia”name that receives the total loss of smellwhich lasts for several months.

The scientists who carried out the research explain that the coronavirus causes anosmia by affecting the olfactory epithelium, an organ responsible for housing the primary sensory neurons that are responsible for detecting odors.

“Usually, patches of respiratory epithelium are interspersed within the region of the olfactory cleft and are composed of secretory cells, ciliated cells, and basal cells. Olfactory sensory neurons detect volatile odors via olfactory receptors located on neuronal cilia in the nasal airspace.”, clarifies the article.

For this reason, he carried out a study on animals, data that he later cross-referenced with human autopsies and came to the conclusion that the loss of smell is due to the fact that Covid generates “alterations in the character of the mucus layer that surrounds its cilia”, as well as “inflammation”.

Why does not smell return after Covid

Although there are several possibilities, the scientists assure that it may be due to severe initial epithelial damage that can eliminate the reserves of basal stem cells, those in charge of renewing the neuroepithelium.

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In addition, prolonged anosmia can be caused by infiltration of the olfactory epithelium by populations of immune cells, known as T cells, something that “disturbs” normal olfactory function.

These hypotheses are based on discoveries in the bodies of people who appeared from Covid-19, in which an infection persists in these cells.

Thus, the study concluded that “ T cell-mediated inflammation persists in the olfactory epithelium long after SARS-CoV-2 has been cleared from the tissue, suggesting a mechanism for long-term post-COVID-19 loss of smell”.

ROC / DE