{"id":22082,"date":"2022-12-21T20:00:23","date_gmt":"2022-12-21T19:00:23","guid":{"rendered":"https:\/\/www.sciencefocus.com\/?p=133898"},"modified":"2022-12-21T21:35:14","modified_gmt":"2022-12-21T20:35:14","slug":"covid-cause-of-long-term-smell-loss-may-have-been-discovered","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/rss_feed\/covid-cause-of-long-term-smell-loss-may-have-been-discovered\/","title":{"rendered":"COVID: Cause of long-term smell loss may have been discovered"},"content":{"rendered":"

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By Jason Goodyer\n \t\t<\/p>

Published: Wednesday, 21 December 2022 at 12:00 am<\/p>

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It has been known since the pandemic emerged in early 2020 that one of the tell-tale signs of being infected with coronavirus<\/a> is a loss of the sense of smell. While most COVID patients recover their sense of smell within a few weeks, for some it persists for months or even years.<\/p>\n

Now, researchers at Duke University Medical Center in the US think they may have figured out why: the infection causes an ongoing immune assault on nerve cells within the nose.<\/p>\n

\u201cOne of the first symptoms that has typically been associated with COVID-19 infection is loss of smell,\u201d said co-researcher\u00a0 Bradley Goldstein<\/a>, an associate professor in Duke\u2019s Department of Neurobiology.<\/p>\n

\u201cFortunately, many people who have an altered sense of smell during the acute phase of viral infection will recover smell within the next one to two weeks, but some do not.<\/p>\n

\u201cWe need to better understand why this subset of people will go on to have persistent smell loss for months to years after being infected with SARS-CoV2.\u201d<\/p>\n

The researchers analysed samples of nasal tissue taken during the biopsies of 24 patients, nine of whom were suffering from a loss of smell associated with long COVID<\/a>.<\/p>\n

They found that T-cells, white blood cells that play a key role in the immune system, were triggering a widespread inflammatory response in the olfactory epithelium. This is a small area found at the top of the nasal cavity where nerve cells that process smells are located.<\/p>\n

The inflammation was on-going despite the absence of detectable SARS-CoV-2 virus.<\/p>\n

\u201cThe findings are striking. It\u2019s almost resembling a sort of autoimmune-like process in the nose,\u201d Goldstein said.<\/p>\n

\u201cWe are hopeful that modulating the abnormal immune response or repair processes within the nose of these patients could help to at least partially restore a sense of smell.\u201d<\/p>\n

The finding also suggests that a similar mechanism could be responsible for other symptoms of long COVID such as brain fog, shortness of breath and fatigue, the researchers say.<\/p>\n