From fragmentation to integration: Can Japan's JIHS deliver a resilient system to deal with health emergencies?

The establishment of the Japan Institute for Health Security (JIHS) in 2025 represents a major institutional reform aimed at enhancing Japan's preparedness for health emergencies in the aftermath of COVID-19. By integrating the National Institute of Infectious Diseases and the National Center for Global Health and Medicine, JIHS seeks to address the long-standing fragmentation of research, clinical practice, and public health responses. In its first year, the institute has made measurable progress in consolidating surveillance and clinical data systems and in expanding research and response networks. However, integration alone does not guarantee effectiveness. Critical challenges remain, including persistent workforce shortages, insufficient incentives for infectious disease research and development, and the complexity of aligning institutional cultures and operational frameworks. This editorial argues that the success of JIHS will depend not only on structural integration but also on sustained investment in human resources, governance reform, and cross-sector coordination. Japan's experience highlights both the promise and the limitations of centralized public health systems and provides important lessons for other countries seeking to build resilient systems to deal with health emergencies.