A group of researchers in London have shown how smell loss associated with the COVID-19 infection differs from what you might typically experience with a bad cold or flu.
Well if despite your loss of smell, you can breathe freely and do not have a runny or blocked nose you have contracted the virus. If your dark chocolate tastes bland or you find nothing sweet in your cup of tea or coffee you do have COVID. Simply put you cannot detect sweet and bitter tastes after contracting the virus.
These findings, published in a journal lend weight to the theory that COVID-19 infects the brain and central nervous system.
The loss of smell and taste is a prominent symptom of COVID-19, however, it is also a common symptom of having a bad cold. Therefore the researchers wanted to determine what exactly differentiates COVID-19 smell loss with the kind of smell loss one might have with a cold and blocked-up nose.
The research team carried out smell and taste tests on 10 COVID-19 patients, 10 people with bad colds and a control group of 10 healthy people - all matched for age and sex.
The virus causes the body's immune system to over-react (a phenomenon known as a cytokine storm) and affects the nervous systemThey wanted to see if their smell and taste test scores could help discriminate between COVID-19 patients and those with a heavy cold.
In the words of one of the researchers, "We know that COVID-19 behaves differently from other respiratory viruses. For example it causes the body's immune system to over-react (a phenomenon known as a cytokine storm) and affects the nervous system. Therefore we suspected that patterns of smell loss would differ between the two groups."
The researchers found that smell loss was much more profound in the COVID patients. They were less able to identify smells, and they were not able to identify bitter or sweet tastes.
This research also shows that there are altogether different things going on when it comes to smell and taste loss for COVID patients, compared to those with a bad cold.
COVID that affects the central nervous system (as deduced from the neurological signs developed by some patients) has similarities with SARS, which has also been reported to enter the brain, possibly via smell receptors in the nose.