As we have understood by now, covid affects each of us differently: there are those who have no symptoms, those who spend ten days in bed with a fever, and those who completely lose their taste and smell. Normally, once the negative swab is obtained, taste and smell return, but some people still cannot smell after months. How come?
According to a new study published in Science Translational Medicine the long-term loss of smell would be due to the fact that olfactory nerve cells continue to fight against inflammation even after the disappearance of the SARS-CoV-2 coronavirus, being decimated in the “fight”.
Excessive immune response. To arrive at these conclusions, the researchers analyzed the olfactory epithelium (the tissue inside the nose where the olfactory nerve cells are located) of people who, after at least four months, had still not recovered the ability to smell. The analysis revealed a widespread infiltration of T lymphocytes, committed to fighting an inflammation still in progress despite the absence of SARS-CoV-2. In addition to this, the researchers found that the number of olfactory sensory neurons had decreased, probably due to the damage suffered by the ongoing inflammation. “The results support the idea that a persistent immune reaction underlies the long-term loss of smell,” explains Sandeep Robert Datta, one of the authors.
long covid. Knowing the damaged areas and the types of cells involved is essential in order to be able to develop targeted treatments: “Modulating the excessive immune response or the reparative processes taking place in the nose of these patients could help to recover at least part of their sense of smell”, explains Bradley Goldstein , one of the authors. What the researchers discovered could be useful for investigating other symptoms of long covidsuch as mental fog, tiredness or shortness of breath, which could be caused by similar inflammatory processes.