Current status of vaccine clinical trials registered on China's Drug Trial Registration and information disclosure platform, 2013–2024

Background: Vaccines are critical tools in global infectious disease prevention, especially amid emerging threats such as COVID-19 and HPV-related cancers. In China, vaccine development has gained momentum due to increasing public health demands and supportive regulatory reforms. However, comprehensive analyses of the broader landscape of vaccine clinical trials remain limited. This study aims to provide a systematic overview of vaccine clinical trials registered in China from 2013 to 2024, examining trends in trial design, phase distribution, vaccine types, and geographic distribution. Methods: We retrieved data from the Drug Trial Registration and Information Publication Platform using keywords including "vaccine," "BCG," and "toxoid." After deduplication and exclusion of non-vaccine entries, 620 eligible vaccine clinical trials were included. Data on trial design, phase, recruitment status, participant demographics, vaccine type, and institutional affiliations. The data were extracted and statistically analyzed by Microsoft Excel 2021, IBM SPSS Statistics version 21andArcGIS 10.8.1, respectively. Results: Among the 620 trials, the majority were parallel-group (84.84%), randomized (81.94%), and double-blind (67.58%). Phase I and III trials accounted for the largest proportions (30.27% and 35.75%, respectively). Influenza (17.1%), HPV (13.4%), and pneumococcal (9.8%) vaccines were the most frequently studied. Most trials were led by CDCs (92.3%) and conducted in eastern provinces, with Jiangsu, Henan, and Guangxi accounting for over half of all trials. The number of registered trials increased steadily from 2013 to 2019, peaking in 2021 and 2023. Conclusions: China has seen consistent growth in vaccine clinical trial activity, supported by regulatory enhancements and public health priorities. While trial volume and geographic spread have expanded, opportunities remain to increase multi-center collaboration, insurance coverage, and diversity in trial phases and vaccine types. These findings provide a foundation for evidence-based policy-making and strategic planning in China's vaccine development landscape.