Correlations Between Olfactory Psychophysical Scores and SARS-CoV-2 Viral Load in COVID-19 Patients

The aim of this study was to evaluate the correlations between the severity and duration of olfactory dysfunctions (OD), assessed with psychophysical tests, and the viral load on the rhino-pharyngeal swab determined with a direct method, in patients affected by coronavirus disease 2019 (COVID-19).

Prospective cohort study.

Patients underwent psychophysical olfactory assessment with Connecticut Chemosensory Clinical Research Center test and determination of the normalized viral load on nasopharyngeal swab within 10 days of the clinical onset of COVID-19.

Sixty COVID-19 patients were included in this study. On psychophysical testing, 12 patients (20% of the cohort) presented with anosmia, 11 (18.3%) severe hyposmia, 13 (18.3%) moderate hyposmia, and 10 (16.7%) mild hyposmia with an overall prevalence of OD of 76.7%. The overall median olfactory score was 50 (interquartile range [IQR] 30-72.5) with no significant differences between clinical severity subgroups. The median normalized viral load detected in the series was 2.56E+06 viral copies/10⁶ copies of human beta-2microglobulin mRNA present in the sample (IQR 3.17E+04-1.58E+07) without any significant correlations with COVID-19 severity. The correlation between viral load and olfactory scores at baseline (R²  = 0.0007; P = .844) and 60-day follow-up (R²  = 0.0077; P = .519) was weak and not significant.

The presence of OD does not seem to be useful in identifying subjects at risk for being super-spreaders or who is at risk of developing long-term OD. Similarly, the pathogenesis of OD is probably related to individual factors rather than to viral load and activity.

4 Laryngoscope, 131:2312-2318, 2021.