Policy lessons regarding medical security for rare diseases inChina: Insights from Zhejiang Province through the multiplestreams framework.

Rare diseases pose a persistent challenge to healthcare systems worldwide due to their low prevalence, high treatment costs, and rapid emergence of novel therapies. In China, while significant progress has been made through national rare disease lists and medical insurance negotiations, substantial medical security gaps remain at the subnational level. This Policy Forum examines the decade-long evolution of rare disease-specific medical security policies in Zhejiang Province (2015-2025) to draw broader lessons for designing sustainable and equitable coverage mechanisms under centralized insurance systems. Using the multiple streams framework (MSF) as an interpretive lens, this article puts forth three policy arguments. First, medical security for rare diseases cannot rely solely on basic medical insurance (BMI); instead, it requires institutional layering that combines insurance-based pooling, fiscal instruments, and social co-assistance. Second, in highly centralized governance contexts, policy entrepreneurship is predominantly state-embedded, with administrative agencies playing a decisive role in coupling problems, solutions, and political mandates. Third, policy innovation in relation to rare diseases is not a one-time event but an iterative process, in which each reform generates new problem definitions and policy windows. The Zhejiang experience demonstrates that under institutional constraints such as standardized benefit lists, local governments can achieve strategic innovation within the available institutional space by shifting their policy focus from reimbursing costs for "drugs on the Nationally Reimbursed Drug List (NRDL)" to targeted compensation for expenditures for drugs not on the NRDL. This pathway improves treatment affordability while maintaining fiscal sustainability, providing actionable insights for China and healthcare systems in other countries facing similar structural constraints.