A health expert said the clinical definition of the new coronavirus should include loss of smell or taste.
A local survey found that a significant number of COVID-19 patients had no other symptoms but a weakened sense of smell or taste. According to the Daegu Medical Association’s poll, about 21 percent of confirmed cases without general COVID-19 symptoms such as sore throat, fever, or chest pain experienced abnormalities in smell or taste.
Professor Song Chang-eun of the Department of Otorhinolaryngology at Myongji Hospital said the American Academy of Otolaryngology-Head and Neck Surgery (AAOHS) and ENT UK, a British group of Ear, Nose and Throat surgeons, regarded olfactory and taste disorders as signs of COVID-19 infection and recommended self-isolation and testing. He made these and other points at a YouTube show Tuesday, by K-Healthlog, a channel operated by The Korea Doctors' Weekly.
Professor Song emphasized that the Korean health authorities should include such symptoms in the clinical definition of the new coronavirus. He pointed out that COVID-19 patients’ experiences of abnormalities in the sense of smell or taste were predictable but overlooked.
“The results from the survey conducted by the Daegu Medical Association on COVID-19 patients in self-isolation did not differ significantly from the incidence of loss of smell in people with a viral infection in the upper respiratory tract,” Song said. “Generally, about 15 percent of patients with a viral infection in the upper respiratory tract experience abnormalities in smell or taste.”
More than 200 viruses could cause upper respiratory tract infections, and most of them can cause loss of smell, the professor noted. “Although there are differences in degree and aspect, a loss of smell may not be the exclusive characteristic of the coronavirus,” he added.
People have not been aware of the issue of the loss of smell or taste, but the recent survey by the Daegu Medical Association drew local and international attention, Song said.
COVID-19 virus can directly attack the nerves in the nasal mucosa, which could cause damage in the olfaction without nasal congestion or runny nose, he added.
Some people can fully recover from a long period of severe cold or flu, following a viral infection in the upper respiratory tract. Still, the loss of smell might persist, and such a scenario is likely for COVID-19 patients who lost the sense of smell, according to Song.
Professor Song also noted that there had been reports of SARS (Severe Acute Respiratory Syndrom) survivors whose loss of smell lasted more than five years. Such cases have not been reported so much as to be statistically meaningful but published in clinical papers or case reviews, he added.
Song emphasized that the clinical definition of suspected COVID-19 infection should include olfactory or taste disorder.
“A significant number of people who had a loss of smell or taste without rhinitis or other cold symptoms tested positive for COVID-19,” he said. “The U.S. association of otolaryngologists and that of British otolaryngologists released statements, recommending self-isolation and testing for those having a smell or taste disorder without other symptoms.”
The U.S. health officials recently included smell and taste disorder in the clinical definition for COVID-19 testing, although the meaning differs in each state, Song said.
Myongji Hospital plans to ask patients with olfactory or taste disorders to get tested at a separated examination room outside the hospital, instead of visiting the otolaryngology department or the family medicine outpatient clinic, he added.
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