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.

Objective: To investigate the incidence of adverse event following immunization (AEFI) with 13-valent pneumococcal polysaccharide conjugate vaccine (PCV13) in Jiaxing City, Zhejiang Province, so as to provide insights into safety monitoring and evaluation of PCV13. Methods: Surveillance data of AEFI with PCV13 in Jiaxing City from 2020 to 2022 were collected from the AEFI Monitoring Information Management System of the Immunization Planning System of Chinese Disease Prevention and Control Information System, including demographic information, vaccination time, time of AEFI occurrence and clinical symptoms, and the reported incidence, population and district distribution, and clinical symptoms of AEFI with PCV13 were descriptively analyzed. Results: Totally 455 cases of AEFI with PCV13 were reported in Jiaxing City from 2020 to 2022, with a reported incidence rate of 232.33/105 doses. There were 431, 21 and 3 cases of general, abnormal, coincidence and psychogenic reactions, with reported incidence rates of 220.07/105 doses, 10.72/105 doses and 1.53/105 doses, respectively, and no reports of causal reaction, vaccine quality accident and vaccination accident. The AEFI cases included 258 boys and 197 girls, with a boy/girl ratio of 1.31∶1, and 288 children at ages of less than a year (63.30%). The largest number of AEFI was reported in Haining City (87 cases, 19.12%), and there were 349 AEFI cases (76.70%) within 24 hours following vaccination. The clinical symptoms mainly included redness and swelling, fever and induration, with reported incidence rates of 132.76/105 doses (260 cases), 109.27/105 doses (214 cases), and 55.66/105 doses (109 cases), respectively. There were 450 cases cured and 5 cases improved in 455 cases of AEFI. Conclusions General reaction is the predominant AEFI in Jiaxing City from 2020 to 2022, with mild symptoms. Most AEFI occurs within 24 hours following vaccination, and has a good prognosis.

Objective: To analyze the surveillance of adverse event following immunization (AEFI) among 8-month-old children in Jiaxing who received measles, mumps and rubella combined attenuated live vaccine (MMR) or measles and rubella combined attenuated live vaccine (MR) , so as to provide support for the adjustment of vaccine immunization strategy. Methods : The AEFI information of MR (December 1, 2016 to April 30, 2018) and MMR (December 1, 2018 to April 30, 2020) was collected through National AEFI Monitoring Information Management System to compare the incidence, clinical features, occurred time of AEFI as well as combined vaccination. Results: Totally 94 287 doses of MR and 79 994 doses of MMR were administered, 145 and 156 cases of AEFI were reported, and the incidence rate was 15.38/10 000 after MR vaccination, which was lower than 19.50/10 000 after MMR vaccination (P<0.05). Most reported AEFI were abnormal reactions, with 93 cases (11.63/10 000) after MR vaccination and 101 cases (10.71/10 000) after MMR vaccination, among which 72 cases (7.64/10 000) and 76 cases (9.50/10 000) respectively had allergic rash. The AEFI cases mainly occurred less than one day after vaccination, with 113 cases (77.93%) after MR vaccination and 125 cases (80.13%) after MMR vaccination. Most cases of AEFI were vaccinated with Japanese encephalitis attenuated live vaccine (JEV), with 103 cases (71.03%) after MR vaccination and 102 cases (65.38%) after MMR vaccination. Conclusions The MMR is safety for 8-month-old children in Jiaxing. Most AEFI cases had abnormal reactions, occur within one day after vaccination, and are vaccinated with JEV.

Objective To evaluate the safety of influenza vaccine and 23-valent pneumococcal polysaccharide vaccine (PPV23) immunized alone or in combination in elderly people and to raise the awareness of vaccine safety among the elderly. Methods From October 2014 to September 2015,454 eld-erly people who were over 60 years old and immunized with influenza vaccine and PPV23 alone or in combi-nation were recruited in this study and divided into five groups. Local and systemic reactions occurred within one month after vaccination were recorded. Results (1) Incidences of adverse reactions among all subjects and people vaccinated with influenza vaccine alone,domestic PPV23 alone,imported PPV23 alone,domes-tic PPV23 combined with influenza vaccine and imported PPV23 combined with influenza vaccine were 10.13%,5.35%,11.63 %,9.52%,17.24% and 12.63%,respectively. Local reaction,injection site pain and mild reaction were the common reactions to vaccination. All reactions occurred within seven days and most of them occurred within 30 minutes to one day after vaccination(82.61%). All subjects recovered within seven days and most of them recovered within one day (84.78%). (2) Compared with the people immunized with domestic or imported PPV23 or influenza vaccine alone,those immunized in combination had higher incidences of reactions to vaccination. Among the three single vaccination groups, domestic PPV23 group had the highest incidence of reactions,followed by imported PPV23 and influenza vaccine groups,but no significant difference was found among them(P>0.05). The incidence of responses to influenza vaccine combined with domestic PPV23 was higher than that to influenza vaccine combined with imported PPV23, but no significant difference was found between them (P>0.05). (3) In each group,women,people aged≥70 years or with chronic diseases had a higher incidence of responses to vaccination than men,people aged 60 to 69 years or without chronic diseases,respectively (P>0.05). Conclusion Immunization with influ-enza vaccine and PPV23 alone or in combination is safe and tolerable in elderly people regardless of gender, age,or whether they are suffering from chronic diseases or not. Both domestic and imported PPV23 have the feature of good safety.