Coronavirus: How to test if you've lost your sense of smell

As experts learn more about coronavirus, studies have found that loss of smell and taste may be key symptoms associated with the virus.

According to one initial study by King’s College London, the symptoms have the potential to be early signs of infection, along with other common coronavirus symptoms such as fever, a dry cough, and tiredness.

Studying responses from more than 400,000 people reported symptoms believed to be associated with coronavirus, the researchers found that 18 per cent said they suffered a loss of smell.

Among the 579 people who were confirmed positive for the virus - out of 1,702 who received a test - 59 per cent had reported loss of sense of smell.

The study, along with other initial reports, have led the American Academy of Otolaryngology-Head and Neck Surgery and ENT UK, an organisation representing ear, nose and throat surgeons in the United Kingdom, to call for the symptom to be added to the coronavirus screening tools.

How can you tell if you are experiencing loss of smell?

While you may not be able to visit a doctor, there are at-home tests you can use to determine whether you are experiencing loss of smell, according to experts.

One test, explained to CNN by Steven Munger, director of the Center for Smell and Taste at the University of Florida, is the “jelly bean test”.

“You take a jelly bean in one hand, and with the other hand you hold your nose tightly so you're not getting any air flow,” he explained. “You put the jelly bean in your mouth and chew it. Let's say it's a fruit flavour jelly bean: if you get the savoury plus the sweetness of the jelly bean you'll know you have functional taste.”

Once the jelly bean is in your mouth and you are still chewing, you release your nose, according to Munger, who explained: “If you have a sense of smell you'll suddenly get all the odours.”

According to Munger, it’s “really a very dramatic, quick, 'Wow' type of response”.

"So if you can go from sweet and sour to the full flavour and know what the flavour is," Munger said, "then your sense of smell is probably in pretty good shape."

If you don’t have jelly beans, you can also do smell tests with household items such as ground coffee or orange peels.

It is important to note, however, that loss of smell is not only associated with coronavirus, as it can be a symptom of many other things, such as the flu or a minor cold, as well as neurodegenerative diseases like Alzheimer's or Parkinson's.

What should you do if you attempt the smell test and cannot smell?

Despite many people who have been diagnosed with Covid-19 or are believed to have the virus reporting a loss of smell, the World Health Organisation has not yet added the phenomenon to its list of coronavirus symptoms.

And, with hospitals and doctors offices overwhelmed, most people who are reporting mild symptoms associated with the virus have been encouraged to stay home.

But, according to Munger, that doesn’t mean you shouldn’t take the symptom seriously - as he says he would put it in the same coronavirus symptom category as fever.

“At this point I would be fairly confident to put it in the same category as, say, fever," said Munger. "Obviously a variety of things can cause a fever. But if you lose your sense of smell quickly you want to self-isolate and contact your physician to talk about what actionable steps you might want to take.”

These steps will likely include self-isolating for 14 days and wearing a mask if you must go out in public.

Munger also notes that the symptom can occur earlier on after you’ve been infected or later - as “there are other patients where the loss of smell kicked in after they were having fever and chills”.

“The timeline is not predictive,” he added.

Fortunately, your sense of smell will likely return. Professor Carl Philpott, director of medical affairs and research at charity previously told The Independent that, like colds, mild congestion of the nose can lead to “post-viral smell loss”.

“If you look at the tissue in detail under the microscope you see that the fine hair-like endings of the receptor cells have fallen off and therefore the cells are no longer able to pick up odour molecules from the nose,” Professor Philpott said, adding that Covid-19 “appears to have a high concentration in the nose”, and that as the majority of anecdotal reports are showing people experiencing transient smell loss that lasts for around seven to 14 days, “it’s probably more likely that the virus is causing some sort of inflammation in the olfactory nerves, rather than it causing any damage to the structure of the receptors”.