Patients report loss of smell in 86% of mild COVID-19 cases — European hospital study

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A reduced sense of smell, or olfactory dysfunction, is one of the most common symptoms of COVID-19. A recent study has examined the symptom’s prevalence and recovery in patients with varying degrees of severity of COVID-19.

In the study of 2,581 patients from 18 European hospitals, the patient-reported prevalence of olfactory dysfunction was 85.9% in mild cases of COVID-19, 4.5% in moderate cases, and 6.9% in severe-to-critical cases. The average duration of olfactory dysfunction reported by patients was 21.6 days, but nearly one-quarter of affected patients reported that they did not recover their sense of smell 60 days after losing it.

Objective clinical evaluations identified olfactory dysfunction in 54.7% of mild cases of COVID-19 and 36.6% of moderate-to-critical cases of COVID-19. At 60 days and 6 months, 15.3% and 4.7% of these patients did not objectively recover their sense of smell, respectively.

“Olfactory dysfunction is more prevalent in mild COVID-19 forms than in moderate-to-critical forms, and 95% of patients recover their sense of smell at 6-months post-infection,” said lead author Dr Jerome R Lechien, of Paris Saclay University.


Study Details
Prevalence and 6‐month recovery of olfactory dysfunction: a multicentre study of 1,363 COVID‐19 patients

JR Lechien, CM Chiesa‐Estomba, E Beckers, V Mustin, M Ducarme, F Journe, A Marchant, L Jouffe, MR Barillari, G Cammaroto, MP Circiu, S Hans, S Saussez

Published in the Journal of Internal Medicine on 5 January 2021


To investigate prevalence and recovery of olfactory dysfunction (OD) in COVID‐19 patients according to the disease severity.

From 22 March to 3 June 2020, 2,581 COVID‐19 patients were identified from 18 European hospitals. Epidemiological and clinical data were extracted at baseline and within the 2‐month post‐infection.

The prevalence of OD was significantly higher in mild form (85.9%) compared with moderate‐to‐critical forms (4.5–6.9%; P = 0.001). Of the 1916 patients with OD, 1363 completed the evaluations (71.1%). A total of 328 patients (24.1%) did not subjectively recover olfaction 60 days after the onset of the dysfunction. The mean duration of self‐reported OD was 21.6 ± 17.9 days. Objective olfactory evaluations identified hyposmia/anosmia in 54.7% and 36.6% of mild and moderate‐to‐critical forms, respectively (P = 0.001). At 60 days and 6 months, 15.3% and 4.7% of anosmic/hyposmic patients did not objectively recover olfaction, respectively. The higher baseline severity of objective olfactory evaluations was strongly predictive of persistent OD (P < 0.001).

OD is more prevalent in mild COVID‐19 forms than in moderate‐to‐critical forms. OD disappeared in 95% of patients regarding objective olfactory evaluations at 6 months.


Wiley material


Journal of Internal Medicine study (Open access)

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