Abstract: Objective To analyze the characteristics of adverse events following immunization (AEFI) after concomitant inoculation of freeze-dried Hepatitis A Attenuated Live Vaccine (HepA-L) with other national immunization program (NIP) vaccines so as to tentatively evaluate the safety of concomitant inoculation and to provide reference for daily concomitant inoculation. Methods Descriptive epidemiology were adopted to analyze AEFI case data of concomitant inoculation of HepA-L with other NIP vaccines between 2013 and 2018, which was collected from the China Information Management System for Immunization Programming. Results A total of 482 AEFI cases were reported due to the concomitant inoculation of HepA-L with other NIP vaccines. Children aged 1 to 2 were the main population. Boys outnumbered girls in these reported cases. A total of ten vaccines were involved in the concomitant inoculation. The top three vaccines that resulted in AEFI cases were MMR, DTaP and JEV-L. When HepA-L was co-inoculated with one of the three vaccines respectively, general reactions accounted for 86.11%-88.69% and abnormal reactions 10.24%~13.89%. A total of 98.21% AEFIs occurred within 3 days of concomitant inoculation, but all the symptoms were improved and no death occurred. Compared with the national AEFI monitoring data on inoculation with NIP vaccine alone, no new abnormal reactions occurred in concomitant inoculation and the risk of inoculation was not increased. Conclusion A recipient who is healthy and has no contraindication to vaccination can be co-inoculated with HepA-L in conjunction with other NIP vaccines. However, the occurrence of rare and severe abnormal reactions should be a focus of attention.

Key words: adverse events following immunization(AEFI), surveillance, freeze-dried Hepatitis A Attenuated Live Vaccine, vaccines for National Immunization Program, concomitant inoculation