Developing a Prioritization Method for Imported Infectious Diseases Using National Notifiable Surveillance Data: The Tokyo 2020 Olympic and Paralympic Games Experience

An increase in imported infectious diseases that are unfamiliar to health professionals was expected during the Tokyo 2020 Olympic and Paralympic Games. The National Institute of Infectious Diseases, Japan, therefore developed a pragmatic quantitative methodology to prioritize imported infectious diseases with the greatest implications for medical and public health workers. This approach selected acute-onset infectious diseases recorded in the national surveillance system and defined 2 indicators: absolute caseload and the relative contribution from importations, reflecting potential workload in diagnosis and acute public health responses, and relative importation impact. We prioritized diseases exceeding predefined thresholds for both indicators. The prioritization results, based on simple calculations, identified 15 prioritized diseases and facilitated transparent nationwide public health planning. With increasing global mobility, this method can serve as a useful tool to improve preparedness for mass gatherings and routine public health planning.