Chronic Spontaneous Urticaria in Hong Kong: Clinical Characteristics, Real-World Practice and Implications for COVID-19 Vaccination

Purpose: The real-world management and clinical characteristics of chronic spontaneous urticaria (CSU) in Hong Kong and its implications for coronavirus disease 2019 (COVID-19) vaccination are unknown. We investigated the clinical characteristics of patients with CSU and the role of an immunologist-led Urticaria Clinic as well as the impact of CSU on COVID-19 vaccine uptake in Hong Kong. Methods: Longitudinal clinical data of 257 CSU patients were collected and analyzed. Association analyses were performed to identify the relationships between variables and factors associated with COVID-19 vaccine uptake.Results: After the immunologist review, the Weekly Urticaria Activity Score (UAS7) was significantly lower than baseline (median: 0.00 vs. 12.0, P < 0.001). Changes in UAS7 were significantly greater among patients with baseline UAS7 >= 16 compared to those with UAS7 < 16 (median: -24.0 vs. -2.00, P < 0.001). CSU patients had lower COVID-19 vaccination rates than the general population with only 176 (68.5%) and 165 (65.0%) receiving at least one dose and 2 doses of vaccination, respectively. The presence of concomitant suspected drug allergy was associated with lower COVID-19 vaccine uptake (odds ratio [OR], 0.47; P = 0.010), while regular pharmacological treatment was associated with higher COVID-19 vaccine uptake among CSU patients (OR, 3.79; P = 0.010).Conclusions: A dedicated immunologist-led Urticaria Clinic may effectively improve CSU management and outcomes in Hong Kong.