Abstract: Objective To analyze the characteristics of adverse events following immunization(AEFI) between 2015 and 2018 in Pingshan District, Shenzhen, and to evaluate the operation of the AEFI surveillance system and epidemiology of AEFI. Methods Cases of AEFI in Pingshan District, Shenzhen were collected between 2015 and 2018 via the National Immunization Program Information Management System as well as the actual vaccination data were analyzed by descriptive epidemiological methods. Results The annual coverage rate of clinical vaccination was 100.0%. A total of 318 cases of AEFI were reported between 2015 and 2018, and the cumulative report rate was 20.35/100,000 doses. Among the 318 cases of AEFI, 69.5% were vaccinated with the first class vaccines, and 30.5% with the second class vaccines. The rate of AEFI was the highest with DaTP(20.4%), and the most frequently reported vaccine was PPV23 with 162.14/100,000 doses. 90.3% of AEFI occurred within 24 hours of vaccination. Common reactions were dominating (71.1%), followed by adverse reactions (27.4%). All these cases were cured or improved. Conclusion The AEFI surveillance system in Pingshan is operating smoothly and the sensitivity is gradually improved. However, it is still necessary to improve the mechanism of vaccination, the quality of data on AEFI monitoring and emergency response to severe AEFI.

Key words: suspected adverse events following immunization, vaccination, monitoring