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Study: Loss of smell in mild COVID cases occurs 86% of the time

We all know to get tested for COVID-19 if we experience symptoms, but during cold/flu and allergy season it’s difficult to decipher between COVID and the “usual” symptoms of seasonal viruses. CNN recently published a new study that offers some assistance in this area – at least for those with mild cases of COVID – including a “smell test”.

Below is an excerpt of the article:

Some 86% of people with mild cases of Covid-19 lose their sense of smell and taste but recover it within six months, according to a new study of over 2,500 patients from 18 European hospitals. The sense of smell reappeared after an average of 18 to 21 days, the study found, but about 5% of people had not recovered olfactory function at six months.

Anosmia, which is a loss of smell, and therefore taste, has been suggested as an early sign of Covid-19. It can occur without any prior warning, not even a stuffy nose. "Anosmia, in particular, has been seen in patients ultimately testing positive for the coronavirus with no other symptoms," according to the American Academy of Otolaryngology-Head and Neck Surgery.

Moderate to severe Covid-19

Comparatively, the study found that only 4% to 7% of people with moderate to severe symptoms of Covid-19 lost their ability to smell and taste. People with moderate Covid‐19 had "clinical signs of pneumonia," the study said, such as cough, fever and difficulty breathing. Those with critical cases of the disease suffered severe respiratory distress, and were more likely to be older and have "hypertension, diabetes, gastric disorders, renal, respiratory, heart, liver and neurological disorders."

The study, which published Monday in the Journal of Internal Medicine, found a higher rate of olfactory dysfunction in younger patients compared to the elderly, but that association needs further analysis, the researchers said.

How to test your sense of smell

Is there anything you can do at home to test to see if you're suffering a loss of smell? The answer is yes, by using the "jellybean test."

"You take a jellybean in one hand, and with the other hand you hold your nose tightly so you're not getting any air flow," Steven Munger, director of the Center for Smell and Taste at the University of Florida, told CNN in a prior interview. "You put the jellybean in your mouth and chew it. Let's say it's a fruit flavor jellybean: if you get the savory plus the sweetness of the jellybean, you'll know you have functional taste," Munger said.

"Then, while still chewing, suddenly release your nose. If you have a sense of smell, you'll suddenly get all the odors and you'll say 'Oh! that's a lemon jellybean,' or 'Oh! that's cherry.' It's really a very dramatic, quick, 'Wow' type of response," he explained. "So if you can go from sweet and sour to the full flavor and know what the flavor is, then your sense of smell is probably in pretty good shape."

The scientific name for this process is retro nasal olfaction, where the odors flow from the back of your mouth up through your nasal pharynx and into your nasal cavity.

But what if you don't have a jellybean? You can use other foods too, said ear, nose and throat specialist Dr. Erich Voigt, director of the division of sleep otolaryngology at NYU Langone Health, in a prior interview.

"The pure smell sense would be if you can smell a particular substance that's not stimulating othermo nerves," Voigt said. "If you can smell ground coffee or coffee brewing, or if you can smell someone peeling an orange -- that's the smell sense."

You have to be careful, though, because it's easy to think you're using your sense of smell when you're not, Voigt said.

"So for example, ammonia or cleaning solutions, those stimulate the trigeminal nerve, which is an irritant nerve," he said. "And so people will think, 'Oh, I can smell Clorox, I can smell ammonia, which means I can smell.' But no, that's not correct. They're not actually smelling, they're using the trigeminal nerve."

Of course, not everyone who flunks a smell test is going to have coronavirus. Any respiratory virus, such as cold or flu, will temporarily impact smell and taste, sometimes even permanently.

A loss of taste is commonly associated with the loss of smell, because we rely on smell to identify flavors. But there can also be medical reasons: Some medications can affect taste; chemotherapy and radiation therapy can certainly disrupt taste; and then there is physical damage, such as nerves severed during dental surgeries.

Read the article in its entirety here.

Sources: CNN and the Journal of Internal Medicine

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