Changes in smell and taste perception related to COVID-19 infection: a case–control study

The main aim of the present study was to psychophysically evaluate smell and taste functions in hospitalized COVID‐19 patients and to compare those results with a group of healthy subjects. Another aim of the study was to assess the relationship of changes in patients’ smell and taste functions with a number of clinical parameters, symptoms, and other physiological signs as well as with severity of disease. Olfactory and gustatory functions were tested in 61 hospitalized patients positive for SARS‐CoV‐2 infection and in a control group of 54 healthy individuals. Overall, we found a significant impairment of olfactory and gustatory functions in COVID‐19 patients compared with the control group. Indeed, about 45% of patients self‐reported complaints about or loss of either olfactory or gustatory functions. These results were confirmed by psychophysical testing, which showed a significantly reduced performance in terms of intensity perception and identification ability for both taste and smell functions in COVID‐19 patients. Furthermore, gustatory and olfactory impairments tended to be more evident in male patients suffering from more severe respiratory failure (i.e., pneumonia with need of respiratory support need during hospitalization).