Risk Assessment Method for Global Monkeypox Importation into China - May 2022-September 2025

In the context of globalization, the risk of cross-border transmission of infectious diseases is continuously increasing. There is an urgent need to develop a scientific, dynamic, and practical tool that captures regional heterogeneity in importation risk, thereby facilitating more targeted prevention and control measures at ports of entry.

We devised an extensible importation risk assessment framework by selecting key indicators through a Delphi expert consultation process and assigning their respective weights using the Analytic Hierarchy Process (AHP). Taking monkeypox (mpox) as a case study, we applied the framework to the global mpox epidemic spanning from May 2022 to September 2025 under three risk scenarios: Clade I, Clade II, and a non-clade-specific (aggregated) scenario. We then analyzed the temporal evolution of major source countries, the spatial distributions of provincial risk levels, and the association between clade-specific importation risk indices and domestically reported mpox cases across the study period.

Our clade-stratified risk assessment framework demonstrates a high degree of consistency and reveals significant disparities between Clade I and Clade II in both international source contributions and provincial vulnerability. The importation risk associated with Clade I is predominantly influenced by Central African countries, particularly the Democratic Republic of the Congo and Uganda. In contrast, the risk related to Clade II is primarily associated with the United States and Southeast Asian nations, such as Thailand and the Philippines. Provincial importation risks generally adhere to a spatial pattern of "east-high, west-low": Shandong Province consistently exhibits a very high risk under Clade I, while Fujian Province maintains a very high risk under Clade II. Notably, the Clade II-specific risk index exhibited a statistically significant positive correlation with national mpox case counts (Spearman's ρ=0.50, P<0.05), whereas the non-clade-specific (aggregated) index did not (ρ=0.32, P=0.12).

This framework effectively captures the structural shift in the sources of mpox importation risk and the regional heterogeneity in risk levels across PLADs in China. It thereby provides a risk-driven decision-support framework for prioritizing port-of-entry screening and tailoring surveillance strategies to high-risk areas.