Scientists from US-based educational institutions such as Duke University and Harvard University analyzed olfactory samples collected from 24 biopsies, including 9 patients with Covid-19 and long-term loss of smell. According to the result, it was revealed that immune cells called T cells attacked the vital nerve cells in the sensitive nasal lining, which are used for smell, and led to the reduction of these cells. This unusual immune response was only seen in patients whose sense of smell was lost for months.
APPROXIMATELY 15 MILLION PEOPLE WORLDWIDE
When the researchers looked at the number of olfactory neurons, they found that those with long-term olfactory loss had significantly fewer olfactory neurons.
According to a research report published in the weekly peer-reviewed medical journal published by the British Medical Association syndicate, at least 5 percent of people who lost their sense of smell during Covid (about 15 million people worldwide) do not regain this sense quickly or fully. (DHA)