Background: Objective data on chemosensitive disorders during COVID-19 are lacking in the Literature.

Methods: Multicenter cohort study that involved four Italian hospitals. 345 COVID-19 patients underwent objective chemosensitive evaluation.

Results:  Chemosensitive disorders self-reported by 256 patients (74.2%) but the 30.1% of the 89 patients who did not report dysfunctions proved objectively hyposmic. 25% of patients presented serious long-lasting complaints. All asymptomatic patients had a slight lowering of the olfactory threshold. No significant correlations were found between the presence and severity of chemosensitive disorders and the severity of the clinical course. On the contrary there is a significant correlation between the duration of the olfactory and gustatory symptoms and the development of severe COVID-19.

Conclusions: patients under-report the frequency of chemosensitive disorders. Contrary to recent reports, such objective testing refutes the proposal that the presence of olfactory and gustatory dysfunction may predict a milder course, but instead suggests that those with more severe disease neglect such symptoms in the setting of severe respiratory disease.