Younger adults with mild-to-moderate COVID-19 exhibited more prevalent olfactory dysfunction in Taiwan

BACKGROUND: Coronavirus Disease 2019 (COVID-19) is rapidly transmitted from person to person, causing global pandemic since December 2019. Instantly detecting COVID-19 is crucial for epidemic prevention. In this study, olfactory dysfunction is a significant symptom in mild to moderate COVID-19 patients but relatively rare in other respiratory viral infections. The Taiwan smell identification test (TWSIT) is a speedy and inexpensive option for accurately distinguishing anosmia that also quantifies the degree of anosmia. Using TWSIT in the outpatient clinic for early identifying the patients with mild to moderate COVID-19 can be promising. METHODS: Nineteen patients confirmed COVID-19 in central Taiwan were collected and divided into two groups: olfactory dysfunction and non-olfactory dysfunction. Demographic characteristics, laboratory findings, and the results of the olfactory test were compared between these two groups. FINDINGS: Thirteen (68.4%) of the 19 patients had olfactory dysfunction. The patients with olfactory dysfunction were younger than those without this symptom. The statistical difference in age distribution was significant between these two groups (IQR: 25.5–35.5 vs. IQR: 32.5–60.3; p-value: 0.012). There was no significant difference in gender, smoking history, comorbidities, travel history, respiratory tract infection symptoms, and laboratory findings between these two groups. CONCLUSION: This study demonstrated that young adults were prone to develop olfactory dysfunctions. In the flu season, olfactory dysfunction is considered a specific screening criterion for early detecting COVID-19 in the community. TWSIT can serve as a decent test for quantifying and qualifying olfactory dysfunction.