Study reports patient-reported loss of smell in 86% of mild COVID-19 cases

A reduced sense of smell, or olfactory dysfunction, is one of the most common symptoms of COVID-19. A recent study published the Journal of Internal Medicine has examined it 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 Jerome R. Lechien, MD, Ph.D., MS, of Paris Saclay University.