Study targets smell loss to sniff out COVID-19

Researchers hope to offer an early warning sign of coronavirus infection by exploring a sudden loss of smell being experienced by a majority of COVID-19 patients. Evidence suggests that more than 60 per cent of COVID-19 patients suffer a loss of smell, called anosmia, as the first symptom of the disease.

“While a sudden loss of smell is relatively rare, it is most commonly caused by an upper respiratory tract infection. It therefore stands to reason that COVID-19 could be causing anosmia,” said Schulich School of Medicine & Dentistry professor Dr. Leigh Sowerby.

As part of the Global Consortium for Chemosensory Research, researchers at Western and Lawson Health Research Institute researchers are asking individuals with confirmed or presumptive cases of COVID-19 to participate in a survey to better understand this symptom.

In the new study, patients with loss of smell will answer questions through a publicly accessible survey. They will be asked about their experiences with COVID-19 and other respiratory illnesses. An immediate goal is to better understand the association between anosmia and COVID-19, and determine if loss of smell is the same in symptomatic and asymptomatic patients. The team also hopes to determine if loss of smell happens before other symptoms of COVID-19 as it could allow for earlier self-isolation advice.

The survey, Global Survey on Respiratory Illnesses and Changes in Smell, Taste, and Flavor, is currently open and available in 10 languages.

“As a sinus surgeon, I see many patients who have lost their sense of smell. It really is the forgotten sense; we don’t appreciate smell until it’s gone,” said Sowerby, a Lawson researcher who is also an otolaryngologist at St. Joseph’s Health Care London. “Smell is a very important part of taste. Imagine if all food tasted like cardboard, and all you could do was make that cardboard taste spicy, salty, sweet or bitter. It can also be a safety concern if you cannot smell a gas leak, burning food or smoke.”

Researchers in the United Kingdom first made note of this with a surge of patients presenting with sudden loss of smell. Many of those patients went on to develop COVID-19.

While there are existing therapies that can aid in regaining a sense of smell, it’s currently unknown whether they are effective for COVID-19 patients.

“We don’t yet know the long-term consequences of anosmia in COVID-19 patients and that’s why this research is important,” Sowerby said. “I encourage anyone who has been diagnosed with COVID-19 or another respiratory illness to complete our survey if able.”

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