Because the start of the pandemic in 2020, experts have been upfront regarding the common symptoms of COVID-19. Considered one of them is the lack of smell, which fits hand in hand with the lack of taste. Most often, patients get well each senses after their bout with the initial infection. Nevertheless, some proceed to suffer smell loss long-term. 

In a recent study published within the journal Science Translational Medicine last week, scientists possibly uncovered why some people fail to get well their sense of smell despite overcoming SARS-CoV-2 infection. Though their research focused on the lack of smell, the findings seemingly make clear other long COVID symptoms with an analogous mechanism, including fatigue, shortness of breath and brain fog.

The team analyzed olfactory epithelial samples collected from 24 biopsies. Nine samples were from patients who had long-term smell loss after COVID-19. Despite the absence of detectable SARS-CoV-2 RNA or protein, researchers identified what was making the long-term problem within the olfactory cells. 

Scientists found that there appeared to be an immune assault on olfactory nerve cells and a decline within the variety of those cells. As well as, T cell-mediated inflammation was also present within the olfactory epithelium long after the virus had been eliminated from the tissue. 

“The findings are striking. It’s almost resembling a form of autoimmune-like process within the nose,” senior creator Bradley Goldstein, M.D., Ph.D. said in a press release. He’s an associate professor in Duke’s Department of Head and Neck Surgery and Communication Sciences and the Department of Neurobiology. 

Goldstein noted that their study was a key step toward designing higher treatments for the difficulty because they now have information on which internet sites get damaged and which varieties of cells are involved in long-term lack of smell. But more research must be done first. 

“We’re hopeful that modulating the abnormal immune response or repair processes throughout the nose of those patients could help to at the very least partially restore a way of smell,” he said. 

In May, a study published in SAGE Journals reported decreasing incidence of chemosensory disruptions with the newer coronavirus variants. This led some scientists to surmise that lack of smell was becoming less common as a symptom of COVID-19 because the virus continues to evolve.