One of the main challenges of COVID-19, the disease caused by the pathogen SARS-Cov-2, is that many people who transmit the disease will show mild symptoms or be asymptomatic, which makes it very difficult to identify how many people are infected with the disease and who might spread it to others.
In fact, in a diagnostic test report for patients in South Korea, one of the most studied countries in relation to the coronavirus, it is concluded that 30% of coronavirus positives also experienced loss of sense of smell, which we know as anosmia.
This is a revealing symptom that is often present even in asymptomatic carriers: sudden loss of smell and, in some cases, of taste.
"What many patients are now reporting is the loss of smell and taste, in many cases abruptly, associated to a greater or lesser degree with symptoms of a viral process that, in the current epidemiological context, make the coronavirus the main suspect", stated the Spanish Society of Neurology.
Although each case is different, the symptoms indicators of the new coronavirus have been widely accepted: high fever, persistent cough or shortness of breath. In the most severe cases, those affected have reported feeling confusion or difficulty breathing, and sometimes anxiety is the most prevalent symptom in all.
The decreased sense of taste and smell caused by COVID-19 remains anecdotal, of course, but a team of British hearing doctors, the nose and throat are asking adults to lose their sense of smell to isolate themselves for seven days to prevent the spread of the disease. For them, it could be an indicator of the coronavirus, so self-isolation is recommended. In addition, a few days ago, the American Academy of Otolaryngology posted on its website a request to include anosmia (loss of sense of smell) and dysgeusia (loss of taste) to the list of symptoms to be considered in a possible COVID-19 infection.
"Coronaviruses have previously been associated with what we call post-viral olfactory loss: it is the loss of smell that persists after a cold. There are many respiratory viruses that can potentially cause problems with odour receptors. So far, with COVID-19, odour loss seems to be transient, but only as time passes will we know how many people have a more permanent loss. We are not yet aware of whether this symptom is common or a sign of a misdiagnosis, but we certainly recommend a warning signal to self-isolate and, if taken into account, may help prevent the spread", explains Carl Philpott, professor of rhinology and olfactology at Norwich Medical School, University of East Anglia, England, to the Science Media Centre.
These "silent carriers" play a key role in the massive spread of the disease, as without the obvious symptoms of persistent fever and cough they cannot be detected by current detection measures.
It is recommended that patients make a call to local health services if they present this symptom for possible treatment or could even help in the early detection of the virus, although it may require nothing more than self-isolation until the infection has passed. Experts are recommending those who experience sudden anosmia to self-isolation, as this would indicate the transmission of the disease, something we are trying to stop by all means.