COVID‐19 Viral Load in the Severity of and Recovery from Olfactory and Gustatory Dysfunction

Cho, Ryan HW; To, Zion WH; Yeung, Zenon WC; Tso, Eugene YK; Fung, Kitty SC; Chau, Sandy KY; Leung, Erica YL; Hui, Thomas SC; Tsang, Steven WC; Kung, KN; Chow, Eudora YD; Abdullah, Victor; van Hasselt, Andrew; Tong, Michael CF; Ku, Peter KM

OBJECTIVES: This study investigated olfactory and gustatory dysfunction in COVID‐19 patients, and their correlations with viral load evaluation. METHODS: This was a prospective cross‐sectional cohort study of 143 symptomatic patients being screened for SARS‐coronavirus 2 (SARS‐CoV‐2) invited to participate. The clinical data of 83 confirmed COVID‐19 subjects were collected, with 60 patients who were symptomatic but negative for COVID‐19 recruited as controls. The prevalence and severity of and recovery time for olfactory and gustatory dysfunction, and cycle threshold (Ct) values from a SARS‐CoV‐2 polymerase chain reaction (PCR) assay of nasopharyngeal and deep throat swabs were collected. Their correlations with Ct values were reported. RESULTS: Thirty‐nine (47.0%) and thirty‐six (43.4%) COVID‐19 patients reported olfactory and gustatory dysfunction, respectively. The results of one‐way ANOVA did not show statistically significant relationships between the Ct values and severity of olfactory and gustatory dysfunction (p = 0.780 and p = 0.121, respectively). Among the COVID‐19 patients who reported smell and taste loss, 28/39 (71.8%) and 30/36 (83.3%) experienced complete recovery, respectively. The mean recovery time was 10.3 ± 8.1 days for olfactory dysfunction and 9.5 ± 6.8 days for gustatory dysfunction. The recovery time was not correlated with the Ct values (Pearson correlation coefficient: smell: ‐0.008, p = 0.968; taste: ‐0.015, p = 0.940). CONCLUSION: There is a high prevalence of olfactory and gustatory dysfunction in COVID‐19. However, the severity of and recovery from these symptoms have no correlations with the viral load of SARS‐CoV‐2. This article is protected by copyright. All rights reserved.