Biliary atresia incidence in Taiwan before, during, and after the COVID-19 pandemic: A nationwide population-based study.

OBJECTIVES: To evaluate whether COVID-19 nonpharmaceutical interventions (NPIs) were associated with changes in biliary atresia (BA) incidence and in late Kasai portoenterostomy in Taiwan. METHODS: We conducted a nationwide population-based cohort study of all confirmed BA cases in Taiwan from January 2004 to December 2023. Monthly BA incidence was calculated per 10,000 live births. COVID-19 policy phases were defined as No NPI (Jan 2004-Dec 2019), NPI (Jan 2020-Nov 2022), NPI-relaxation (Dec 2022-Feb 2023), and Post-NPI (Mar-Dec 2023). Phase-specific incidence rate ratios (IRRs) were estimated using Poisson regression with live births as an offset and calendar-month fixed effects. Late Kasai was defined as portoenterostomy performed at age > 60 days; phase differences were assessed using logistic regression. RESULTS: A total of 586 infants with BA were identified (overall incidence 1.55/10,000). Crude incidence was 1.52/10,000 in No NPI (485 cases), 1.64/10,000 in NPI (73), 0.90/10,000 in NPI-relaxation (3) and 2.18/10,000 in Post-NPI (25) Compared with No NPI, adjusted IRRs were 1.08 (95% confidence interval [CI] 0.84-1.38) for NPI, 0.58 (0.19-1.82) for NPI-relaxation, and 1.46 (0.98-2.19) for Post-NPI. The proportion of late Kasai decreased from 35.3% in No NPI to 16.0% (4/25) in Post-NPI (odds ratio 0.38, 95% CI 0.14-1.08). CONCLUSION: The incidence of BA in Taiwan did not decline during the COVID-19 NPI period, suggesting limited impact of reduced infectious exposure on BA occurrence. A trend toward fewer late Kasai procedures in the post-NPI phase may reflect improved early detection or care delivery.