An international research team led by scientists from the Arizona State University has shown that for patients who have a respiratory infection, the loss of smell is the most indicative symptom of COVID-19. In the case of the SARS-CoV-2 coronavirus infection, it is also a neurological symptom caused by the invasion of the nervous tissue, so that it could be differentiated from other diseases in which the sense of smell is also lost. temporary.
Loss of smell is the most indicative symptom of COVID-19
Next to the fever, shortness of breath and dry cough, loss of taste and smell, have been the “key” symptoms to identify that a patient had been infected by it coronavirus SARS-CoV-2, but now, the last of these is perhaps the most significant in the wake of new research, focused on the diagnosis of COVID-19 in the presence of a respiratory disease.
As we already know, in fact, loss of smell can also occur with other types of respiratory infections, like a simple cold or flu, but in these cases we lose our sense of smell because the nose closes and we may develop rhinorrhea (runny nose). In the case of COVID-19, however, it is a neurological symptom , linked to the fact that the pathogen attacks the olfactory nerve and bulb , the “preferential route” by which the coronavirus attacks the brain. It is not strange then that those patients with Covid, can continue breathing without problem, since your nose is not actually clogged with secretions as is often the case with colds or the flu.
Studies on the matter
To confirm this theory, there are several studies that add to the first mentioned. Thus, an abundant international research team has shown that anosmia is due to COVID-19 in most patients with a respiratory infection. The co-authors of the research that has been carried out include the professor Alexander Wieck Fjaeldstad, a professor specializing in smell and taste in the University of Aarhus, Denmark. The scientist said that thanks to a test capable of evaluating chemosensory changes, the loss of smell scored around 80 on a scale ranging from 0 to 100, which makes it the most indicative symptom of COVID-19. This underscores how important it is to watch out for this symptom, as “It could be the only symptom of the disease”the expert said in a press release.
He The result is comparable to that of a research carried out by scientists at University College London, in which it was shown that of 600 patients with anosmia, up to 80 percent of them had been infected with the coronavirus SARS-CoV-2. In addition, 40 percent of those who were positive also had loss of smell as the sole symptom of COVID-19.
In patients with COVID, the anosmia can last much longer than what happens with other infections. Only half of the patients who participated in the international study had regained their sense of smell 40 days after diagnosis. «This differs from the picture we see with other viral infections and causes long-term discomfort for patients, both in relation to food and social contact, while at the same time worrying them »said Professor Wieck Fjaeldstad.
In the new study, which involved more than 4,500 patients from 23 different countries, it was shown that even taste alteration (disgeusia) is a symptom that strongly characterizes COVID-19. In this case, the score on the scale from 0 to 100 was 70. «While the loss of smell itself eliminates the ability to smell food, the simultaneous loss of other senses makes it difficult to process who you are. eating. Putting food in your mouth can therefore become a decidedly unpleasant experience», Explained the expert.
OdoR-19 screening
The loss of smell is so significant that the authors of the study, led by scientists from the Department of Life Sciences at Arizona State University, developed a unique screening to evaluate loss of smell in patients, called OdoR -19.
«To help clinicians and contact people For the identification of individuals with a high probability of having COVID-19, we propose a new 0-10 scale for screening for recent olfactory loss, the ODoR-19», the experts write in the study summary. “We found that numerical scores ≤2 indicate high probabilities of symptomatic COVID-19 (4 <10). Once independently validated, this tool could be used when viral lab testing is impractical or are not available », pointed out the scientists of the research called “Recent smell loss is the best predictor of COVID-19 among individuals with recent respiratory symptoms” and that it was published in the magazine Chemical Senses.
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