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Olfactory and Gustatory Dysfunctions as a Clinical Presentation of Mild-to-Moderate Forms of the Coronavirus Disease (COVID-19): a Multicenter European study

Our take —

Among a group of European patients with SARS-Cov-2 infection, olfactory and gustatory complaints were common (>80%). Olfactory dysfunction may be the first symptom of COVID-19 disease, including in otherwise asymptomatic individuals. Study participants may have been more likely to have olfactory and gustatory symptoms than the population of all COVID-19 patients, so the high prevalence should be interpreted with caution.

Study design

Case Series

Study population and setting

417 adult non-ICU patients and health care workers (mean age 36.9 years, 63% female) with mild or moderate laboratory-confirmed SARS-CoV-2 infection, recruited from 12 hospitals in Belgium, France, Spain, and Italy.

Summary of Main Findings

86% of respondents had at least one olfactory symptom and 89% reported taste dysfunction. Of the patients with olfactory complaints, 80% were anosmic and 20% had reduced smell. In all, 18% of patients with COVID-19 did not experience either nasal obstruction or rhinorrhea, yet 80% of these patients nevertheless reported olfactory dysfunction. Of patients experiencing an olfactory complaint, 12% of patients reported that the olfactory dysfunction preceded the appearance of other symptoms. 73% of patients with olfactory dysfunction regained their olfactory function within 8 days of the resolution of other symptoms.

Study Strengths

This is the most comprehensive assessment of olfactory and gustatory complaints in COVID-19 disease to date. The data were collected from multiple sites in Western Europe using validated questionnaires.

Limitations

Because symptoms are assessed retrospectively, they are subject to recall bias. Health care workers’ participation may have been related to the presence of olfactory or taste dysregulation. The timing of symptom onset may be particularly imprecisely recalled. Olfactory and gustatory deficits were not objectively measured and may be misclassified. Finally, there is no information on the proportion who declined participation, raising further questions about potential selection bias.

Value added

This study suggests that SARS-CoV-2 may present with olfactory and gustatory complaints, including as a first symptom. Results show a much higher prevalence of these symptoms than in other studies.