Abstract
ObjectivesOlfactory dysfunction (OD) is a common symptom of Coronavirus Disease 2019 (COVID-19). Although many patients have been reported to regain olfactory function within the first month, long-term observation reports vary. Therefore, we aimed to assess the course of chemosensory function in patients diagnosed with COVID-19 within 3–15 months after the infection.MethodsOne hundred and two patients (71 females and 31 males; mean age 38.8 years) diagnosed with laboratory-confirmed COVID-19 and subjective OD participated in this single-center study 111–457 days after onset of OD. Patients first performed chemosensory tests at home, followed by psychophysical testing (Sniffin’ Sticks (TDI), 27-item Candy Smell Test (CST), Taste Strips Test (TST)) in the clinic. Questionnaires regarding importance of olfaction (IOQ) and olfactory-specific quality of life (QOD) were applied at both timepoints.ResultsAfter a mean 216 days (SD 73; range 111–457) between OD onset and follow-up testing, the mean Sniffin’ Sticks (TDI) score was 27.1 points (SD 5.8; range 4.25–38.5): 4.0% were anosmic, 72.5% hyposmic, and 23.5% normosmic. At follow-up testing, 73.5% of patients reported improvement, 5.9% deterioration, and 20.6% no change in OD. Moreover, full recovery of self-perceived smell, flavor, and taste was not observed. According to questionnaires, the individual importance of smell did not change, but participants showed improvement in OD-related quality of life (p < 0.001) and had increased parosmia scores (p = 0.014) at follow-up.ConclusionOur results show that long-lasting OD after SARS-CoV-2 infection is a common symptom. The majority of patients had OD in the range of hyposmia, which was confirmed by comprehensive smell tests.
Highlights
Since the first reported human infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in December 2019 in Wuhan, China, [1] coronavirus disease 2019 (COVID-19) has spread throughout the world [2]
It consists of three parts evaluating negative statements, positive statements, and parosmia score
Orthonasal olfactory function was measured by the comprehensive Sniffin’ Sticks test battery (TDI, Burghart Medical Technology, Wedel, Germany) [19]
Summary
Since the first reported human infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in December 2019 in Wuhan, China, [1] coronavirus disease 2019 (COVID-19) has spread throughout the world [2]. Loss of chemosensory function has been assessed by psychophysical smell/taste tests. Reports on the duration of COVID-19-related OD have revealed that, 2 months after OD onset, 45% were diagnosed as hyposmic and 1% anosmic as measured by the TDI test [11]. 5 weeks after symptom onset, 37% had persistent smell loss [12]. Observations of OD related to COVID-19 over a more extended period are still rare
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
