A Comparative Evaluation of Taste and Smell Dysfunction in COVID-19: A Cross-sectional Study

Introduction: Taste and smell dysfunction are hallmark symptoms ofCoronavirus Disease (COVID-19). While objective assessment of chemosensory function is critical for accurate evaluation, most prior studies have relied on self-report measures, and data from non-Western populations remain limited. Objective: To objectively assess gustatory and olfactory function in recently diagnosed COVID-19 patients compared to age- and sex-matched healthy controls using validated tools in an Iranian population. Methods: In this prospective cross-sectional study, 30 COVID-19 patients and 30 matched healthy controls were enrolled between February and March 2022 in Tehran, Iran. Gustatory function was assessed using the Waterless Empirical Taste Test (WETT), and olfactory function was evaluated using the Pocket Smell Test (PST). Results: COVID-19 patients demonstrated significantly lower mean WETT scores compared to controls [16.14 (SD= 4.06) vs. 18.73 (SD=5.06), p < 0.05], with sour, bitter, and umami tastes significantly affected. Smell scores were also significantly lower among patients [6 (Interquartile Range (IQR)=5–7) vs. 7 (IQR=6–8), p < 0.05]. Among COVID-19 patients, 10% were anosmic and 56.7% microsmic. The odds of smell dysfunction were significantly higher in the COVID-19 group (OR = 4.67, 95% CI: 1.57–13.87). Conclusion: COVID-19 is associated with measurable impairments in both gustatory and olfactory function, particularly in sour, bitter, and umami modalities. There wasn’t any correlation between olfactory and gustatory test scores.