[Evaluation of bilateral vaccine cooperation priority countries on Chinese human papillomavirus vaccine using hierarchical K-means hybrid clustering].

OBJECTIVE

To evaluate priority target countries and formulate context-specific cooperation modalities for China ' s bilateral international collaboration on human papillomavirus (HPV) vaccines, thereby furnishing an evidence-based reference for optimizing China ' s bilateral vaccine cooperation stra-tegies and contributing to global health equity.

METHODS

Using a previously established index system designed for selecting preferred countries in China ' s international vaccine cooperation, we comprehensively applied a weighted-scoring approach to quantitatively rank 29 Phases 3 and 4 Global Alliance for Vaccines and Immunization (Gavi) eligible countries in HPV vaccine cooperation. Based on 5 first-level index (legal and regulatory factors, economic factors, political factors, social factors, and technological factors) scores, a hierarchical K-means hybrid method was used for clustering the countries. Hierarchical clustering was initially utilized to explore the underlying data structure and determine the optimal number of clusters, followed by K-means clustering to precisely categorize the evaluated nations based on their multidimensional characteristics.

RESULTS

The top10 countries were mostly Asian countries. African countries were mostly in the lower ranks. The countries were clustered into three types: (1) Technology transfer priority (n=3: Indonesia, Viet Nam, Uzbekistan), characterized by above-average economic, techno-scientific and political scores, robust vaccine-import volumes, non-negligible domestic manufacturing capacity and high political stability-recommended for priority collaboration; (2) Basic assistance (n=25), approximating mean indicator values, typically low-population or low-income economies suitable for aid-based or concessional-procurement models; (3) High barrier (n=1: India), exhibiting high socio-demographic and scientific base yet minimal legal-regulatory scores, indicating large demand, established vaccine industry, but formidable registration barriers. Policy recommendations included: concessional product export plus clinical-trial cooperation with Indonesia, with prospective licensing and technology transfer; clinical-trial collaboration with Viet Nam; and licensing/technology-transfer schemes with Uzbekistan.

CONCLUSION

Indonesia, Viet Nam, and Uzbekistan are identified as the priority target countries for China ' s bilateral international cooperation on HPV vaccines. For these technology-transfer priority nations, cooperation should be strategically conducted through diverse modalities encompassing vaccine product export, clinical trial collaboration, authorized licensing, and technology transfer.