Spatiotemporal heterogeneity of online HIV self-testing sales and its potential driving factors in China, 2015–2020: a retrospective nationwide study

Since the UNAIDS introduced HIV self-testing in 2014, its application has been widely adopted globally. Developed in China approximately 2015, HIV self-testing (HIVST), which involves the online purchase of testing kits via e-commerce platforms, has emerged as the most significant distribution method. This approach offers numerous benefits, including user-friendliness, speed, and enhanced privacy protection. To understand the spatiotemporal heterogeneity of online HIVST purchasing behavior and its potential driving factors in China. The online retail sales data of HIVST kits from the two largest e-commerce platforms in China from 2015 to 2020 were collected for this study. The Bayesian spatiotemporal hierarchical model (BSTHM) was used to investigate the spatiotemporal characteristics and identify the rapidly growing high-demand regions of online HIVST kit sales. Furthermore, the BSTHM was used to identify potential driving factors associated with online sales, including college students per 10,000 persons, GDP per capita, net per person, phone per person, population density, road density and HIV screening cases per 10,000 persons. From 2015 to 2020, the sales of online HIVST kits experienced a dramatic surge, increasing from 837,061 kits to reaching 7,827,411 kits annually, with a total of 23,987,155 kits sold, with annual peak sales in December. Four economically superior regions in China, the Pearl River Delta, Yangtze River Delta, Beijing-Tianjin areas, and Shandong Peninsula, presented relatively high spatial preferences for online purchased HIVST kits. Thirty-eight rapidly growing high-demand regions were identified, which were located mainly in northeastern China (28.9%, 11/38), the Pearl River Delta (28.9%, 11/38) and the Beijing-Tianjin areas (15.8%, 6/38). The number of college students per 10,000 persons, GDP per capita, net per person, population density and number of HIV screening cases per 10,000 persons were identified as the driving factors that were positively associated with the online purchase rate of HIVST kits. Our study illuminates the spatiotemporal dynamics and driving factors behind online HIVST kit sales across mainland China, offering pivotal insights for crafting detailed HIVST guidelines. We pinpointed regions with significant sales demand, guiding policymakers in resource reallocation and HIV care continuum optimization, particularly in identified critical ' rapidly growing high-demand’ regions.