Surveillance of adverse events following immunization with inactivated influenza vaccines among the elderly in Huzhou City / 预防医学

ABSTRACT

Objective@# To investigate the incidence of adverse events following immunization (AEFI) with inactivated influenza vaccine among the elderly in Huzhou City, Zhejiang Province, so as to provide insights into safety monitoring and evaluation of inactivated influenza vaccines.@*Methods@#Data pertaining to surveillance on AEFI with inactivated influenza vaccines among the elderly at ages of 60 years and older in Huzhou City from 2020 to 2022 were collected from the AEFI Monitoring Information Management System of the Immunization Planning System of Chinese Disease Control and Prevention Information System, including demographics, time of AEFI occurrence, classification of AEFI and clinical syndromes, and the reported incidence and epidemiological features of AEFI with inactivated influenza vaccines were analyzed using a descriptive epidemiological method. @*Results@#Totally 84 elderly cases at ages of 60 years and older were reported with AEFI with inactivated influenza vaccines in Huzhou City from 2020 to 2022, with a reported incidence rate of 9.83/105 doses, and the reported incidence rates of AEFI with trivalent and quadrivalent inactivated influenza vaccines were 9.74/105 doses and 48.71/105 doses, respectively. The reported incidence rates of general, abnormal, coincidence and psychogenic reactions were 7.96/105 doses, 1.52/105 doses, 0.23/105 doses and 0.12/105 doses, respectively, and no vaccine quality accidents or wrong vaccine administered were reported. The cases with AEFI included 52 women and 32 men, and most cases were aged from 60 to 69 years (44 cases, 52.38%). The highest incidence of AEFI was reported in Nanxun District (17.94/105 doses), and there were 79 cases (94.05%) with AEFI within 24 hours following vaccination. The clinical symptoms mainly included fever, local redness and swelling, and local induration, with reported incidence rates of 2.22/105 doses, 3.74/105 doses, and 1.99/105 doses, respectively.@*Conclusions@#The reported incidence of AEFI with inactivated influenza vaccines is low among the elderly at ages of 60 years and older in Huzhou City, with general reactions as predominant AEFI, and most AEFI occurs within 24 hours following vaccination.