Abstract:Abstract: OBJECTIVE To evaluate the current status and safety of concurrent administration of pertussis-containing vaccines in Congqing.METHODS Vaccination records and adverse events following immunization(AEFI)data for pertussis-containing vaccines among children in the Chongqing born between September in 2023 and Auqust in 2024 were collectedfrom the Chongqing Immunization Program Information Management System and the National AEFI Surveillance System.The current status of concurrent administration and AEFI incidence rates were described.RESULTS A total of 374,676 doses of pertusis-containing vaccines were administered,of which 212,159 doses(56.62%)were given concurrently with other vaccines.The concurrent vaccination group reported 212 AEFI cases,with a reported incidence rate of 99.93/100,000 doses administered.Among these,208 cases(98.04/100,000 doses)were general reactions,and 1 case(0.47/100,000 doses)was an abnormal reaction reported.The single-vaccination group reported 341 AEFI cases,with an incidence rate of 209.82/100,000 doses administered.Among these,336 cases(206.75/100,000 doses)were general reactions,and 1 case(0.62/100,000 doses)was an abnormal reaction following single administration of DTaP-IPV/Hib. CONCLUSION Both monovalent and combined administration of pertussis-containing vaccines demonstrate excellent safety profiles. It not only provides evidence-based support for promoting combined vaccination within routine immunization programs but also lays a crucial foundation for developing and implementing more scientifically sound and efficient non-routine combined vaccination strategies in the future.