Loss of taste and smell occurs in patients from both the coronavirus and from common flu but new research published in the journal Rhinology suggests there’s a big difference between the two. In covid19 patients it is much more severe than in common flu ones, this could be due to the effect covid19 has on the nervous system and the brain, according to British researchers.
Professor of Rhinology at the University of East Anglia and who was also involved in the research Carl Philpott said that covid19 behaves differently to other respiratory viruses as it causes the immune system of the body to over-react, known as a cytokine storm, and it also affects the nervous system. So he and his team believe that loss of smell and taste will be different in the two groups.
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The researchers studied the taste and smell function in 10 healthy people, 10 covid19 patients, and 10 acute cold patients. They found that not only the loss of taste and smell in covid19 patients was significantly worse than both the healthy individuals and the cold patients but the ability to detect bitter tastes and sweet tastes was also particularly impaired in covid19 patients. Philpott said that it is particularly interesting that the coronavirus particularly affects bitter and sweet taste receptors as they are known to play an important part in innate immunity.
Both the flu patients and covid19 patients in the study reported improvement in their sense of smell and taste over time, but only 30% of the patients with covid19 reported complete recovery. The researchers said that it is likely that the coronavirus patients will experience constant loss of taste even after recovery from the virus.
There were some limitations with the study including the small sample size, so more research is needed to find out if similar findings occur in a bigger group of coronavirus patients. Philpott and his team said that as taste and smell tests were able to discriminate between flu patients and covid19 patients so these tests could be used as an additional screening tool for people with coronavirus.
According to the researchers the loss of taste in coronavirus patients was not only more severe but a different mechanism in the olfactory system, which is responsible for the sense of smell of the body, caused it. The researchers believe that according to their findings coronavirus is causing a direct loss of the ability to taste in its patients rather than loss of taste due to impairment in the sense of smell. Coronavirus has the ability to produce increased inflammation in the body and this inflammation can damage taste receptors, according to the researchers. They believe there is a possibility that it affects the part of the brain stem which is connected to the sense of taste.
The US Centers for Disease Control and Prevention has included a ‘new loss of taste or smell’ in the list of coronavirus symptoms to look out for. The symptom is more common in moderate or mild cases of the coronavirus and may appear at the beginning of the illness, and may also be the first indication that you are infected.