What smell and taste disorders by SARS-CoV-2 do we know? Predictive value of the Venezuelan Olfactory Test and RT-PCR molecular analysis in COVID-19 infection

Background: Smell and taste disorders are reported very frequently and at an early stage in SARS-CoV-2 infectious disease. These symptoms could be sensitive and specific to establish possible severity of the infection, and may suggest the flow of decisions as to further therapy. Objective: We asked whether smell and taste impairment are earlier and more sensitive symptoms than the RT-PCR molecular assays for SARS-CoV-2 detection. Methods: Subjects (N=275) with a probable COVID-19 diagnosis were classified as follows: Symptomatic with chemosensory dysfunction, symptomatic without chemosensory dysfunction, and asymptomatic. Validated unbiased testing of the chemosensory dysfunction was performed by means of the Venezuelan Olfactory Test and taste test. Nasal swabs and blood samples were analyzed by RT-PCR molecular analysis a rapid diagnostic test to detect the SARS-CoV-2 virus and viral antibodies, respectively. Smell and taste testing and RT-PCR were performed every 3 to 5 days to patients until full recovery. Results: Out of 144 patients that were positive for SARS-CoV-2: 45.83% had COVID-19 symptoms, smell and taste disorders; 23.61% had COVID-19 symptoms but not smell or taste disorders, and 30.55% were asymptomatic. Mild hyposmia and hypogeusia were frequently associated with SARS-CoV-2 symptoms. Recovery from chemosensory dysfunction occurred between day 3 and 14. RT-PCR becomes negative after 21 days. The Venezuelan Olfactory Test and taste test has a 61.68% positive predictive value, 45.83% sensitivity, and 68.7% specificity for SARS-CoV-2. Conclusions: Smell and taste disorders are associated symptoms with SARS-CoV-2 infection, but not a predictor of the disease, as compared to the molecular RT-PCR test.