Understanding Public Attitudes Towards Human Papillomavirus Vaccination in Japan: Insights from Social Media Stance Analysis Using Large Language Models

BackgroundDespite the reinstatement of proactive human papillomavirus (HPV) vaccine recommendations in 2022, Japan continues to face persistently low HPV vaccination rates, posing significant public health challenges. Misinformation, complacency, and accessibility issues have been identified as key factors undermining vaccine uptake. ObjectiveThis study aims to understand how factors such as misinformation, public health events, and attitudes toward other vaccines, like COVID-19, influence HPV vaccine hesitancy, by analyzing the evolution of public attitudes towards HPV vaccination in Japan by examining social media content. MethodsWe collected tweets related to HPV vaccine from 2011 to 2021. Traditional natural language processing (NLP) methods and large language models (LLMs) was utilized to perform stance analysis on collected data. The analysis included stance identification, time series analysis, topic modeling, and logic analysis. We framed our findings within the context of the WHOs 3Cs model--Confidence, Complacency, and Convenience. ResultsPublic confidence in the HPV vaccine fluctuated in response to government policies and media events, with misinformation playing a critical role in eroding trust. Complacency increased following the suspension of recommendations in 2013 but decreased as advocacy resumed in 2020. Accessibility (Convenience) was also found to be a key determinant of vaccination uptake. HPV vaccines are often used as supportive evidence towards other vaccines, such as COVID-19. ConclusionsOur findings underscore the importance of targeted public health interventions to restore and maintain vaccine confidence in Japan. While vaccine confidence has shown a slow increase, sustained efforts are necessary to secure long-term improvements. Confidence in one vaccine may positively influence perceptions of other vaccines. Addressing misinformation, reducing complacency, and enhancing vaccine accessibility are key strategies to improve uptake. Increased confidence in HPV vaccines appeared to have a positive influence on confidence in other vaccines, such as COVID-19. This study also demonstrates the utility of LLMs in offering a deeper understanding of public health attitudes. To effectively combat vaccine hesitancy and improve coverage, interventions must prioritize consistent communication, localized strategies, and an integrated approach to vaccine narratives.