In coronavirus-infected patients, hyposmia and dysgeusia are common and can precede the systemic symptoms thus indicating central nervous system involvement.

A retrospective study was performed to explore the prevalence of dysgeusia and hyposmia in subjects having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their temporal relationship with the emergence of the symptoms.

Analysis of the individuals admitted to the non-intensive coronavirus disease (COVID-19) unit based on a positive swab test and/or of clinical radiological signs of coronavirus infection was done. Using a standardized questionnaire, the patients were interviewed. The laboratory and clinical data were gathered. The data were assessed with descriptive statistics and the findings were expressed as 95% confidence intervals and  point estimates.

Of 141 admitted subjects, about 93 subjects were interviewed. In 58 cases (62.4%), dysgeusia and hyposmia were present. In 22.4% of subjects, gustatory and olfactory impairment preceded the systemic symptoms. In both the arms, the presence of active smoking was very limited: 8.6% in hyposmic subjects compared to 2.9% in normosmic subjects [odds ratio= 3.2]. Furthermore, the total leukocytes and neutrophils count were found to be 23% [effect estimate 1.23] and 29% [effect estimate 1.29] lower in the hyposmic cohort. No considerable differences were witnessed for other biomarkers of inflammation.

Intensive searching of hyposmia and dysgeusia should be done. Quick close monitoring and isolation should be done until the confirmation or disapproval of the infection. An early phase virus-stimulated cytopenia may be indicated by a decline in the number of total leukocytes and neutrophils in hyposmic patients.

Dysgeusia and hyposmia are common in SARS-CoV-2 infected subjects.