Does COVID-19 cause permanent damage to olfactory and gustatory function?

The objective of this study was to investigate the status of COVID-19 patients with sudden anosmia and dysgeusia using an olfactory dysfunction questionnaire highlighting recovery times. This prospective study included 75 patients who completed a patient-reported outcome questionnaire. Among these, 46 patients completed an olfactory evaluation based on the duration of anosmia and dysgeusia. The olfactory evaluation revealed that 24% (N = 18) of patients had mild hyposmia, 13% (N = 10) had moderate hyposmia, 30% (N = 23) had severe hyposmia, 32% (N = 24) had anosmia, and 100% had dysgeusia (N = 75). The viral load significantly decreased throughout the 17 days following the onset of the olfactory disorder. The purpose of this study was to understand whether patients with COVID-19 can recover olfactory and gustatory function, in contrast to patients with other rhinoviruses and inflammatory diseases such as rhinosinusitis chronic and rhinosinusitis with polyps. These preliminary clinical findings indicate that the relatively rapid recovery of olfactory and gustative function can mean a resolution of viral infection in most patients. The present study suggests that coronavirus can induce olfactory dysfunction but not permanent damage. Olfactory and gustatory functional impairment has been recognized as a hallmark of COVID-19 and may be an important predictor of clinical outcome. Our study supports the need to add anosmia and dysgeusia to the list of symptoms used in screening tools for possible COVID-19 infection.