Abstract：Objective To analyze the occurrence characteristics of adverse events following immunization（AEFI）in Ningbo and to provide the basis for evaluating the safety of vaccine. Methods The AEFI case data from 2009 to 2016 were collected by the Chinese Adverse Events Following Immunization Information Management System and the Chinese Immunization Planning Information Management System. The descriptive analysis was used for AEFI reporting time,demographic characteristics,classification,outcome and vaccine distribution. Results From 2009 to 2016,5 036 AEFI cases were reported. The average incidence rate was 18.36 per 100 000. The most of the cases were reported from May to August,which accounted for 44.18%. The most of cases were occurred in the infant group（≤ 1 year old）,which accounted for 66.30%. The highest incidence rate was occurred in the age group of 6 years,which was 47.87 per 100 000. Among 5 036 cases of AEFI,4 946 cases were vaccine reaction,accounting for 98.21%. The most of symptoms were fever,swelling and indurations,accounting for 84.69%. There were 4 523 cases（89.81%）of AEFI occurred within two day after vaccination. The incidence rate of Non national immunization program vaccine （19.59 per 100 000） was higher than that of national immunization program vaccine （17.89 per 100 000）（P<0.05）. Except 151 unknown,96.86%（4 878/5 036）cases were improved and recovered. Three cases of sequelae were all coincidence event. Among the 4 cases of death,in addition to 1 case of systemic disseminated BCG infection,3 of the other cases were coincidental event. Conclusion AEFI cases occurred mainly in the infant group and occurred within two day after vaccination. In general,the safety of vaccines was satisfied.
