Seven out of ten patients were affected by each of these two symptoms, concludes the study published in the Journal of Intern Medicine and carried out on more than 1,400 patients with infection with the new coronavirus confirmed by a screening test.
The other most common symptoms were a stuffy nose (67.8%), coughing (63.2%) and fatigue (63.3%), followed by muscle pain (62.5%), a nose that runny (60.1%) and loss of taste (54.2%). In contrast, fever was reported by less than half of the patients (45.4%).
This first epidemiological survey of European patients with a non-severe form of COVID-19 was launched by the International Federation of ENT Societies (IFOS), to assess the frequency of symptoms of loss of smell (anosmia) and taste (ageusia), reported by some patients since the arrival of the pandemic on the European continent.
Their preliminary results published in early April had shown the frequency of these symptoms, little described until now by studies in Asia.
Their comprehensive study in five European countries (France, Belgium, Italy, Spain and Switzerland) confirms that the loss of smell is “a specific symptom” of COVID-19, and not just the consequence of nasal obstruction.
“The ability of COVID-19 to invade the olfactory bulb and, therefore, the central nervous system, is probably a path” to explain the anosmia, points out the Foch hospital.
Anosmia and ageusia have been described very little in studies in Chinese patients, which mainly reported fever, cough and difficulty breathing as symptoms of COVID-19.
The IFOS study believes that this difference can be explained by the fact that the Chinese studies focused on hospitalized patients with more severe forms of infection.
The authors also hypothesize that successive genetic mutations in the coronavirus could be the cause of different symptoms, and that European populations have a higher level of angiotensin 2 converting enzyme, or ACE2, which acts as a coronavirus receptor.
They also point out that the frequency of symptoms varies according to age and sex.
Thus, young patients more often have ENT disorders (ear, nose and throat) while older patients often have fever, fatigue and loss of appetite.
Cough and fever are more common in men, with women being more affected by loss of smell, headache and stuffy nose.
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