Objective  To analyze the occurrence of inactivated enterovirus 71 (EV71) vaccine-related adverse events following immunization (AEFI) among children and to evaluate the safety of the vaccine for providing evidences for the promotion and use of the vaccine.

  Methods  Passive and active surveillance data on EV71 vaccine-related AEFI reported in Jinhua city, Zhejiang province from September 2016 through December 2019 were extracted from China Information System for Planned Immunization Management and analyzed with descriptive statistics.

  Results  During the 4-year period in the city, totally 391 AEFI were reported among 401 505 doses of inactivated EV71 vaccine vaccination, with a reported incidence rate of 97.38 per 100 000 doses; the reported incidence rate differed significantly by year (χ² = 80.835), administrative region (χ² = 71.920), vaccine type (χ² = 31.609), and dose time (χ² = 19.955) (P < 0.001 for all); the most of the reported AEFI were general reactions (n = 365), only 15 were abnormal reactions and 11 were coincidence diseases; 82.86% of the AEFI occurred within one day after the inoculation, and the main abnormal reaction was allergic rash. For active surveillance among 6 084 children with a total of 9 090 doses of vaccination during the period, 59 AEFI were identified, and the detection rate was 649.06 per 100 000 doses; there were no significant gender, month age, and dose time differences in the detection rate (all P > 0.05) but the detection rate differed significantly by vaccine type (P < 0.001); the most (96.61%) of the AEFI occurred within 30 minutes to 3 days after the vaccinations and 72.88% of the AEFI were fever; all the AEFI recovered in the observation period.

  Conclusion  Among the children in Jinhua city, the main inactivated EV71 vaccine-related AEFI are general reactions occurred within 3 days after vaccinations, indicating that the vaccination of the vaccine is safe for the children.