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Over 50% of healthcare workers infected with SARS-CoV-2 report that their sense of smell has not returned to normal 5 months after infection.
Findings show that olfactory problems are common not only in the acute COVID phase but also in the “long term” and that these problems need to be “taken into account” when following up on these patients. I will. The Department of Anatomy at the University of Quebec in Trois Rivieres, Quebec, Canada Medscape Medical News.
Loss of smell affects eating and drinking, which can affect quality of life and even be dangerous, Frasneri said. “If your sense of smell is impaired, you may not unknowingly eat spoiled food or smell smoke or gas in your house,” he said.
In addition, Frasunelli has a higher proportion of olfactory deficits. depression..
The findings will be presented at the 2021 Annual Meeting of the American Academy of Neurology (AAN) in April.
Studies show that about 60% of COVID patients lose some sense of smell during the acute phase of their illness. “But we wanted to go further and investigate the long-term effects of odor and taste loss,” Frasneri said.
The analysis included 813 healthcare workers in Quebec. For all patients, SARS-CoV-2 infection was confirmed by testing with a nasopharyngeal swab.
Participants completed a 64-item online survey asking about the following three sensations: Taste, which includes tastes such as sweet, sour, bitter, salty, tasty, and umami. The trigeminal nerve contains sensations such as the spiciness of chili peppers and the “coolness” of mint.
They were asked to rate these on a scale of 0 (no perception) to 10 (very strong perception) before, during, and now. They were also asked about other symptoms, including fatigue.
Most respondents were infected with the first wave of the virus in March and April 2020 and completed the survey five months later on average.
The majority of respondents (84.1%) were women, but Frasunelli said it was not surprising, as women dominate the healthcare sector.
According to the analysis, the average odor rating was 8.98 before infection, 2.85 during the acute phase, and 7.41 when respondents answered the questionnaire. Taste was less affected than olfaction and recovered faster. Taste results were 9.20 before infection, 3.59 in the acute phase, and 8.05 after COVID.
Of the 580 respondents who showed decreased olfaction during the acute phase, the average olfactory rating when responding to the questionnaire was 6.89 compared to 9.03 before infection. More than half (51.2%) reported that they had not regained full olfactory function.
The fact that half of the participants did not return to normal olfaction for a long time after infection was “innovative and very impressive,” Frasneri said.
But this does not necessarily mean that everyone with an impaired sense of smell “has a big problem,” he said. In some cases, he said the problem was “more subtle.”
Isn’t it a CNS issue?
Respondents also completed the Chemosensory Dysfunction Home Test (CD-HT). They were asked to prepare common household foods such as peanut butter, sugar, salt and vinegar in a particular way. It provides feedback on these odors and tastes, for example by adding sugar or salt to the water.
In this CD-HT analysis, 18.4% of respondents reported persistent loss of odor. According to Frasnelli, this adds to the evidence from the self-reported response, suggesting that in some cases the problem is more than a return to normal sensation.
“According to a survey, about 50% say their sense of smell hasn’t returned to normal yet, and a CD home test shows that nearly 20% of subjects do have a fairly strong sense of smell. “He said.
Frasnelli stated that most of the samples were female, but the results showed no gender differences. “Gender data is a bit distorted, so it’s hard to see the data,” he said.
Male respondents were older than female participants, but there was no difference in disability between age groups. Frasneri said this was “very interesting.” This is because older people usually lose some odor.
Researchers have not yet investigated whether the results vary by type of health care worker.
They have also not investigated in detail whether the severity of the infection affects the risk of long-term olfactory dysfunction. Some studies suggest that odor problems are common when they are less severe, because Frasunelli says that odor loss is not a major problem for patients fighting serious health problems. I pointed out that there is a possibility.
For other symptoms, many respondents reported prolonged malaise. Some reported debilitating malaise, Frasnelli said. However, he warned that this would be difficult to interpret, as the participants were health care workers, many of whom returned to work during the pandemic and were probably not completely rested.
He also said that he and his colleagues “did not link” the degree of olfactory dysfunction and fatigue.
The COVID virus appears to attack the supporting cells of the olfactory epithelium rather than the nerve cells.
“For now, the odor problem seems to be a peripheral problem, not a central nervous system problem,” Frasunelli said. “But I’m not sure. The virus can somehow invade the brain and the effects of the infection on the brain can cause symptoms.”
Researchers extend the study with a separate questionnaire to assess sensation 10-12 months after COVID.
The limits of the study include the subjective nature of odor and taste assessments and the single point in time when the data were collected.
Comments on the study of Medscape Medical News, Thomas Hummel, MD, Otorhinolaryngology, Professor of Olfactory University, Dresden, Germany, said new results on olfactory loss after COVID are “very consistent” with what he and his colleagues have observed. ..
Studies show that one in five people infected with SARS-CoV-2 experience olfactory loss. “The numbers may vary slightly from study to study or from laboratory to laboratory, but I think 5% to 20% of patients after COVID will show long-term olfactory loss,” Hummel said.
His group observed that “more have not returned to normal.” This is in line with what Frasneri’s work revealed, Hummel said.
Also comment Medscape Medical NewsKenneth L. Tyler, MD, a professor of neurology at the University of Colorado School of Medicine in Denver, Colorado and a fellow at the American Academy of Neurology, said the study was relatively large and the results were “interesting.”
Tyler “provides more evidence that there is a subset of symptomatic patients well beyond the acute phase” of COVID, but the results are “almost confirmatory” and “surprisingly.” There is nothing. “
However, the researchers said they tried to make the study “a little more quantitative” and “confirm self-reports with a validated CD home test.”
Tyler wondered how representative the sample was and whether the study attracted more participants with sensory impairment. “Once the smell and taste are gone, we’re likely to answer such a survey,” he said.
He also noted the difficulty of distinguishing between odor loss and taste loss.
“If you lose your sense of smell, things don’t taste right and you can be confused about how to separate the two,” he said.
This study was supported by the University of Quebec at Trois Rivieres and the Quebec Foundation. Frasnelli received a royalties from Austria’s Styriabooks for a book on olfaction published in 2019 and a reward for his lecture activities. Hummel and Tyler do not disclose the relevant financial relationship.
American Academy of Neurology (AAN) 2021 Annual Meeting: Summary 2192, due to be announced on April 20, 2021.