Loss of smell, altered taste present in half of COVID-19 cases

Loss of smell (anosmia) and altered taste (dysgeusia) could provide clue for diagnosing COVID-19

Nearly half of individuals who contract COVID-19 experience changes in their sense of taste and smell, found two new research.

In a review published in the journal Gastroenterology, researchers found that nearly half of COVID-19 patients experience changes to their sense of taste.

Researchers analyzed data from five studies conducted between mid-January and the end of March. Of the 817 COVID-19 patients studied, 49.8% experienced changes to their sense of taste. Researchers suspect the true prevalence could be even higher because some of the studies were based on reviews of patient charts, which may not have noted every symptom.

“We propose that this symptom should be one of the screening symptoms in addition to the fever, shortness of breath and productive cough. Not just for suspected COVID patients, but also for the general population to identify healthy carriers of the virus,” said Dr. Muhammad Aziz, chief internal medicine resident at UToledo and the paper’s lead author.

anosmia and dysgeusia were the most distinctive symptoms associated with SARS-CoV-2 infection and that these symptoms could be severe, as shown by the complete loss of perception of odours such as coffee and garbage

Taste disorders are tied to a variety of viral illnesses. Researchers theorize that loss of taste sensation could be due to COVID-19’s ability to bind to what’s known as the ACE-2 receptor, which is expressed in epithelial cells on the tongue and mouth.

In a similar study, among 2883 adults tested for SARS-CoV-2, in the Eastern Townships in Quebec between March 10 and March 23, 2020, researchers identified 134 positive cases. Almost two-thirds (63%) of these people reported either loss of smell, changes in taste or both symptoms, compared with 8% in the control group who did not have SARS-CoV-2. Results were published in CMAJ (Canadian Medical Association Journal).

“We found that anosmia and dysgeusia were the most distinctive symptoms associated with SARS-CoV-2 infection and that these symptoms could be severe, as shown by the complete loss of perception of odours such as coffee and garbage,” wrote Dr. Alex Carignan, Medical Microbiologist and Infectious Diseases consultant at CIUSSS de l’Estrie – CHUS, Sherbrooke, Quebec.

“These symptoms should be considered as common and distinctive features of SARS-CoV-2 infection and should serve as an indication for testing and possible retesting of people whose first test result is negative,” added the authors.

The findings add to research from USA, Italy and Germany that reported altered smell and taste in a majority of people who tested positive for SARS-CoV-2.