Objective To explore the application of the prevention, preparation, response, and recovery (PPRR) theory in the cross-departmental collaboration in the prevention and control of infectious diseases in the China International Import Expos (CIIEs) held in every November in Shanghai from 2018 to 2024, thus providing an empirical basis and theoretical reference for optimizing the cross-departmental collaboration mechanism under regular prevention and control.

Methods We collected the epidemic prevention and control work plans, emergency response plans, technical guidelines, summary reports, and relevant epidemic cases handled by Shanghai Center for Disease Control and Prevention during the CIIEs from 2018 to 2024. The case analysis method was used to analyze the practices and achievements of cross-departmental collaboration in the prevention, preparation, response, and recovery phases based on the PPRR model.

Results An efficient information collaboration mechanism was established based on an innovative "1+6+N" cross-departmental command architecture. The work in the prevention phase encompassed establishing a cross-departmental and multi-dimensional risk assessment model, adopting a layered monitoring strategy, and strengthening health monitoring. In the preparation phase, a modular prevention and control plan library was established, consisting of work plans, emergency plans, and technical guidance or operation manuals. In addition, cross-departmental joint training and exercises were conducted, and emergency material reserves were reasonably allocated to improve the response speed. In the response phase, a "4 h plus 12 h" disposal requirement was strictly implemented. Public health, security and CIIE bureau teams were mixed as an emergency response group and divided into several units. The interval between risk identification and risk confirmation as well as between risk confirmation and risk management was strictly controlled through risk hierarchical management. During the recovery phase, full-process post evaluation was conducted to solidify experience and promote optimization of resource allocation and disposal processes while assessing the effectiveness of the response. Upon evaluation, the above measures are expected to be effective to increase the risk warning time to within 30 minutes and reduce the overall emergency decision-making and response time to 10% of that under the conventional model. Therefore, Shanghai achieved "zero infection" of epidemics and "zero transmission" of imported diseases.

Conclusions The collaborative mechanism architecture constructed based on the PPRR model can be used for the research of cross-departmental collaborative mechanisms in mass gatherings. In the future, cross-departmental collaboration on infectious disease prevention and control in mass gatherings can be further promoted in three dimensions: mechanism innovation, technological empowerment, and collaborative governance.