Surveillance results of adverse events following immunization with meningococcus-containing vaccine in Jiaxing City
DU Zhequn1, TANG Xian1, YU Pengfei1, GAN Zhengkai2, SONG Yiping1, HU Jie1
1. Jiaxing Center for Disease Control and Prevention, Jiaxing, Zhejiang 314050, China; 2. Xiuzhou District Center for Disease Control and Prevention, Jiaxing, Zhejiang 314031, China
Abstract：Objective To investigate the occurrence of adverse events following immunization (AEFI) with meningococcus-containing vaccine (MCV) in Jiaxing City, Zhejiang Province from 2020 to 2024, so as to provide the evidence for MCV safety monitoring and evaluation. Methods AEFI surveillance data following MCV vaccination were collected through the Immunization Program Information Management System of the China Disease Prevention and Control Information System, and MCV vaccination data were collected through the Zhejiang Provincial Immunization Program Smart Service Information System. Descriptive analyses were performed to examine the demographic distribution, temporal distribution, and regional distribution of AEFI cases, as well as the doses of MCV administered, the interval between vaccination and AEFI onset, clinical symptoms of AEFI, and outcomes. Results From 2020 to 2024, a total of 263 AEFI cases were reported in Jiaxing City, with an average annual reported incidence of 27.73/105 doses, showing an increasing trend (P<0.05). Common adverse reactions predominated, accounting for 230 cases (87.45%), with the reported incidence of 24.25/105 doses. Among AEFI cases, 139 (52.85%) were males and 124 (47.15%) were females. The majority of cases were aged <2 years, accounting for 156 cases (59.32%). The number of reported AEFI cases was relatively high in the second and third quarters, with 75 and 77 cases, accounting for 28.52% and 29.28%, respectively, and reported incidence of 29.48/105 doses and 29.71/105 doses, respectively. Haiyan County and Pinghu City reported relatively higher numbers of cases, with 44 cases each, accounting for 16.73% each, and reported relatively higher AEFI incidence of 58.91/105 doses and 40.46/105 doses, respectively. Following the 1st, 2nd, 3rd, and 4th doses of MCV, 136, 111, 14, and 2 AEFI cases were reported, accounting for 51.71%, 42.21%, 5.32%, and 0.76%, respectively, with reported incidence of 30.63/105 doses, 23.24/105 doses, 55.59/105 doses, and 120.63/105 doses, respectively. A total of 198 AEFI cases (75.29%) were reported within 1 day after MCV vaccination. Among common adverse reaction cases, the predominant clinical symptoms were fever and local redness/swelling, occurring in 151 and 49 cases, accounting for 57.41% and 18.63%, respectively, with reported incidence of 15.92/105 doses and 5.17/105 doses, respectively. Conclusions From 2020 to 2024, the average annual reported incidence of AEFI following vaccination with five types of MCV in Jiaxing City was relatively low, but an increasing trend was observed. Common adverse reactions predominated. AEFI cases were concentrated in children aged <2 years, with relatively higher incidence in summer and autumn, as well as in Haiyan County and Pinghu City. Most cases occurred after the first dose of MCV and within 1 day post-vaccination, with fever and local redness/swelling being the main clinical symptoms.
