Understanding conversations about health issues on Chinese social media platforms: A study of the HPV vaccine on Weibo

Digital health and social media have reshaped public health discourse by enabling broader lay participation. Yet, sociological research on how citizens discuss health topics in Chinese digital spaces remains limited. Building on theorisations of lay expertise, mis/disinformation, conspiracy theory and responsibility, this study examines how lay users engage with topics related to the human papillomavirus (HPV) vaccine on Sina Weibo: how content circulates and changes over time, what information and sources are drawn upon, and how vaccine responsibility is negotiated. A mixed-methods approach combined longitudinal analysis of Weibo posts (2016– 2022) with semi-structured interviews. The text analysis identified key themes, while interviews explored users’ perspectives, reasoning, and trust in greater depth. Findings reveal a diverse online conversation that merges official news, practical advice, and personal stories of vaccination or cancer fears. However, rumours and conspiracy theories are also present – e.g., infertility concerns or “Western plot” claims. Lay participants often act as peer educators, blending personal anecdotes with external information (e.g., medical facts or news articles), demonstrating lay expertise in action. Debates over responsibility for vaccination are prominent, with many framing it as both an individual obligation and a familial concern, particularly emphasising maternal roles and occasionally the involvement of male partners. These discussions highlight the moral and gendered dimension of vaccine acceptance and questions of trust and risk. By focusing on the Chinese context, the study broadens digital health engagement research and demonstrates that established theories on lay expertise and vaccine hesitancy apply, yet with distinctive local dynamics. Integrating big data analytics with qualitative inquiry provides a comprehensive understanding of health discussions, encompassing both online (Weibo-based) and offline contexts. These insights can inform public health communication, facilitating culturally tailored interventions that address misinformation, foster trust, and enhance HPV vaccine uptake.