Surveillance of suspected adverse events following immunization in Chongchuan District from 2008 to 2022
GU Hong1, HOU Xiaoyan2, QI Zhigang1, WU Ming1
1. Department of Immunization Planning, Chongchuan District Center for Disease Control and Prevention, Nantong, Jiangsu 226001, China; 2. Nantong Center for Disease Control and Prevention, Nantong, Jiangsu 226001, China
Abstract：Objective To investigate the incidence of suspected adverse events following immunization(AEFI) in Chongchuan District, Nantong City, Jiangsu Province from 2008 to 2022, so as to provide insights into safety assessment of vaccines. Methods The data on AEFI surveillance in Chongchuan District from 2008 to 2022 were collected through the National Immunization Program Information Management System of China, including demographics, history of vaccination, laboratory tests, incidence of AEFI and clinical characteristics. The epidemiological, clinical characteristics and reported incidence of AEFI were analyzed in Chongchuan District from 2008 to 2022 using a descriptive epidemiological method. Results The reported incidence of AEFI in Chongchuan District from 2008 to 2022 appeared a tendency towards a decline (P<0.05), and the annual average reported incidence was 50.85/105. The incidence of AEFI associated with vaccines included in the national immunization program was significantly higher than that caused by vaccines that were not included in the national immunization program (74.67/105 vs. 20.35/105, P<0.05). General reaction was the predominant type of AEFI (1 937 cases, 44.21/105), and there were 274 cases with abnormal reactions (6.25/105) and 17 cases with coincident syndromes (0.39/105); however, no vaccine quality or vaccination accidents occurred. A high incidence rate was seen in AEFI associated with vaccines administered by subcutaneous (75.05/105) and intramuscular injection (47.40/105), and a low incidence rate was found in AEFI associated with vaccines administered orally (16.41/105). The five highest reported incidence rates of AEFI were found for the combined diphtheria, tetanus, acellular pertussis, poliovirus and Haemophilus influenzae type b vaccine (312.01/105), 7-valent pneumococcal polysaccharide-protein conjugate vaccine (292.14/105), inactivated Japanese encephalitis vaccine (248.37/105), Group ACYW135 meningococcal polysaccharide vaccine (240.67/105) and combined live vaccine for measles and rubella (229.31/105). The general reactions mainly included fever, redness and swelling and induration (1 878 cases, 96.95%), and abnormal reactions mainly included allergic skin rash (241 cases, 87.96%). In addition, 91.34% of AEFI occurred within 24 hours after vaccination, and 99.73% of cases with AEFI were cured during the 3-month follow-up. Conclusions The reported incidence of AEFI appeared a tendency towards a decline in Chongchuan District from 2008 to 2022. General reaction was the predominant type of AEFI, and all AEFI showed a good prognosis. The safety of vaccines was high in Chongchuan District from 2008 to 2022.
