Abstract:Abstract: OBJECTIVE To analyze the monitoring status of suspected adverse event following immunization (AEFI) in Cheng⁃ guan District of Lanzhou from 2019 to 2023,in order to understand the characteristics,reported incidence rate,types of adverse reactions,and sensitivity of AEFI monitoring in Chengguan District. METHODS The AEFI monitoring related modules of the China Disease Prevention and Control Information System and the Immunization Planning module of the Gansu Provincial Comprehensive Management Platform for Disease Prevention and Control were used to collect data on AEFI reported cases from 2019 to 2023,as well as the number of vaccine doses administered. The incidence of adverse reaction reports, types of adverse reaction vaccines, and other characteristics were analyzed using Excel. From 2019 to 2023,a total of 2 107 AEFI cases were reported in Chengguan District of Lanzhou,with a cumulative reported incidence rate of 76.55/10 5 doses; General reactions accounted for 98.72%,abnor⁃ mal reactions accounted for 0.33%,coupling diseases accounted for 0.90%,and psychogenic reactions accounted for 0.05%. The reported incidence rates were 75.57/10 5 , 0.25/10 5 , 0.69/10 5 , and 0.03/10 5 , respectively. There were no vaccination accidents or vaccine quality accidents reported. CONCLUSION From 2019 to 2023,the adverse reactions of AEFI in Chengguan District were mainly general reactions,while allergic reactions were the main abnormal reactions,and severe abnormal reactions were extremely rare. In addition,the sensitivity of abnormal reaction monitoring in 2023 has significantly improved compared to 2021 and 2022, indicating that the effectiveness of the monitoring system is constantly improving.