Half of COVID-19 cases may experience altered sense of taste: Study

Nearly 50 per cent of people who contract COVID-19 may experience altered or lost sense of taste, according to a review of studies.

The review, published in the journal Gastroenterology, could provide diagnostic hint for clinicians who suspect their patients might have the deadly disease.

"Earlier studies didn't note this symptom, and that was probably because of the severity of other symptoms like cough, fever and trouble breathing," said Muhammad Aziz, from the University of Toledo in the US.

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"We were beginning to note that altered or lost sense of taste were also present, not just here and there, but in a significant proportion," Aziz said.

The research team analysed data from five studies conducted between mid-January and the end of March.

Of the 817 patients studied, 49.8 per cent experienced changes to their sense of taste, according to the study.

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The researchers noted that 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-19 patients, but also for the general population to identify healthy carriers of the virus," Aziz said.

Previous studies have found that a significant number of people who have COVID-19 don't know they have been infected, and may be spreading the disease.

The researchers suspect an altered sense of taste is more prevalent in patients with minor symptoms. However, they said more studies are needed to validate that suspicion.

The researchers said changes in an individual's sense of taste could be a valuable way to identify carriers who are otherwise mostly asymptomatic.

They theorise that the reason behind loss of taste could be the ability of the virus to bind to what's known as the ACE-2 receptor, which is expressed in epithelial cells on the tongue and mouth.

The researchers said the drip of new information shows the need for more scientists to dig into the impacts of COVID-19.

"A lot of things are being missed, which is why I think researchers from every field should try to look into this and see if it's affecting their specialty in one way or another," Aziz added.