Abstract：Objective To evaluate the safety of enterovirus 71（EV71）inactivated vaccines produced by Wuhan Institute of Bio Products through learning the incidence of adverse events following immunization（AEFI）in children aged 6 months to 3 years old after vaccination. Methods According to the national requirement for vaccine safety monitoring program，data of AEFI cases after inoculated EV71 vaccines from September 2017 to October 2018 in Zhejiang Province was collected by combining active and passive monitoring. Demographic characteristics，space distribution，dose and incidence of AEFI were analyzed. Results A total of 107 503 children were included in this study，of which 27 173 were actively monitored and 80 330 were passively monitored. The monitoring results showed that 288 cases of AEFI occurred after inoculated EV71 vaccines，the reported incidence rate was 267.90/100 000. Of 288 cases，266 cases had common reactions（247.43/100 000），14 cases had abnormal reactions（13.02/100 000）and 8 cases had complications（7.44/100 000）；145 cases were passively monitored（180.51/100 000）and 143 cases were actively monitored（526.26/100 000）；150 cases were males and 138 cases were females，with the males to females ratio of 1.09∶1. The AEFI of EV71 vaccines were reported in all the cities of Zhejiang Province，with Jinhua，Taizhou and Hangzhou ranking the top three and accounting for 50.69% of all the reported cases. About 202 cases of AEFI（70.14%）occurred after the first dose of EV71 vaccines，and 163 cases（56.60%）occurred on the day of inoculation.Most of common reactions were fever，swelling and sclerosis. The harm of the reported abnormal reactions was mild，with 8 cases of anaphylactic rash and no other serious abnormal reactions were found. Conclusion The reported incidence rate of AEFI of the domestic EV71 vaccine in children aged from 6 months to 3 years is 267.90/100 000，without serious abnormal reactions，suggesting that the EV71 vaccine is safe.
