Taste and smell perception in hospitalized COVID-19 patients : preliminary insights

Since the onset of the coronavirus disease pandemic, taste and smell dysfunctions have been identified as distinct features of SARS-CoV-2 infection. However, most reports on COVID-19–related taste and smell loss has relied on questionnaires or self-reported data while objective studies based on psychophysical evaluation in these patients are lacking. The aim of this study is to evaluate the gustatory and olfactory function, using psychophysical objective methods, in COVID-19 patients treated at the IRCCS Istituto Auxologico Italiano. 45 hospitalized patients with naso-pharyngeal swab positive for SARS-CoV-2 infection (F: 53.8%, age range: 40-85 y.o.) were recruited. Identification and intensity were measured for 12 odors. The taste function was assessed by means of four taste strips and identification as well as intensity are measured for each primary taste. An index was calculated for taste and smell functions, by summing the scores provided for intensity and identification, to obtain a clinical classification of smell and taste functions. As previously described in literature data, self-reported data underestimated the patients’ chemosensory dysfunctions during the infection’s course (37.8%). Instead, our interesting results based on objective evaluations showed that over than 80% of patients revealed a certain degree (mild to severe) of residual hyposmia (37 out of 45) or hypogeusia (36 out of 45). Any significant chemo-sensitive dysfunctions have been highlighted in relation to gender, age or days from symptoms onset. Furthermore, obese patients reported a reduced overall taste score (p<0.05). Work is now in progress to achieve a larger sample size and to compare the results obtained with those of a control group of healthy subjects. To conclude, this is one of the first study that objectively evaluated taste and smell loss in hospitalized patients during SARS-CoV-2 infection. The acquisition of reliable data is fundamental to understand mechanisms behind these symptoms in COVID-19 infection and might provide new insights into aspects of viral pathogenesis.