((A-275)) (A-275) Monitoring Incidence of Acute Pancreatitis Following COVID-19 Vaccination compared with Background Incidence in Korea

Background: Acute pancreatitis has been reported as a potential adverse event following COVID-19 infection or COVID-19 vaccination. Although there have been case reports of acute pancreatitis following COVID-19 vaccination, a population-based assessment has not been reported.

Objectives: To evaluate the relative incidence rate ratio of hospitalization due to acute pancreatitis between the observed and background incidence rates following COVID-19 vaccination.

Methods: We conducted a cohort study of patients aged 18 years or older using a large database based on the national health information database (January 2002 to December 2023) from the national health insurance service (NHIS). The occurrence of acute pancreatitis was defined as hospitalization with a diagnosis of new-onset acute pancreatitis (International Classification of Diseases, 10th revision code K85) between 2011 and 2023. Using the autoregressive integrated moving average model, we constructed a prediction model based on sex- and age-standardized monthly incidence rates per 100,000 population per month from January 2011 to February 2021. We then compared the actual observed incidence rates with the background incidence rates from March 2021 to December 2023.

Results: Among the 747,466 patients hospitalized with a diagnosis of acute pancreatitis between 2011 and 2023, 89,887 patients with a previous history of the condition were excluded, and 657,579 patients with incident acute pancreatitis were identified. The age- and sex-standardized background incidence rate of acute pancreatitis was 11.226 per 100,000 population per month, while the observed incidence rate was 9.862 per 100,000 population per month. Incidence rate ratio (95% confidence interval; p-value) was 0.91 (0.44–1.67; 0.920) in acute pancreatitis.

Conclusions: The incidence of new-onset acute pancreatitis was numerically lower than the background incidence rate; however, the difference was statistically nonsignificant. The comparison between the observed and background rates serves as substantial evidence supporting the safety profile of COVID-19 vaccination and will contribute to effective safety monitoring in the future infectious diseases, newly developed vaccines, and therapeutics.