First considered secondary or anecdotal, the alteration or loss of smell and / or taste, following infection with SARS-CoV-2, actually turns out to be an important marker for Covid-19. This is the major conclusion of a study conducted by Jérôme Lechien (Hôpital Foch, Suresnes) and Sven Saussez (university of Mons, Belgium), to be published in the review European Archives of Oto-Rhino-Laryngology. These studies show that such sensory alterations occur in 80% to 90% of the cases studied in Europe and regress rapidly for almost half of the subjects. Researchers are still recruiting patient volunteers to obtain more long-term data.
The authors interviewed 417 patients with mild or moderate Covid-19 symptoms from ten European hospitals. 85.6% and 88% of these patients respectively report an alteration in smell or taste, women being significantly more affected than men.
The vast majority of patients without nasal blockage have also experienced such manifestations of the disease. About 12% have seen disturbances in smell and taste before the other symptoms of the disease – dry cough, fever, body aches, respiratory problems. Anosmia (total loss of smell) and dysgeusia (taste alteration) should therefore be considered as early markers of the disease, argue the authors.
Among the patients questioned by the authors, 44% recovered their sense of smell and / or taste less than two weeks after the end of the major symptoms of the disease. “The first surprising thing is that this coronavirus also produces anosmia so frequently in patients. This is not something common for other viral diseases that eventually produce this kind of effect, explains the otolaryngologist Stéphane Hans, co-author of this work. The second surprise is that these anosmias can regress as quickly. Again, this is relatively unusual. Certain influenza viruses can for example induce irreversible anosmias. “
As for half of the patients affected by Covid-19 who did not quickly recover their sense of smell or taste, “It is reasonable to expect that a large number of them will regain their olfactory and taste functions in the following weeks”, write the researchers.