Background: In the context of social media vaccine campaigns, understanding the impact of message framing on audience engagement is crucial. This study examines the efficacy of messages centered on efficacy versus autonomy, informed by theoretical frameworks: the Extended Parallel Process Model (EPPM) and Self Determination Theory (SDT).
Methods: Utilizing the Facebook A/B Split Test (FBST) feature, an online experiment was conducted to compare the response to two different messages: one emphasizing vaccine efficacy (EPPM-informed) and the other focusing on individual autonomy in making vaccine decisions (SDT-informed). The primary measure of interest was the number of clicks on a link directing to a pro-vaccine website.
Results: The findings indicated that the autonomy-centered (SDT-informed) message resulted in a significantly higher click-through rate to the pro-vaccine website, particularly among users aged 65 and above. Furthermore, analysis of comments from Facebook users identified factors potentially contributing to vaccine hesitancy, with mistrust being the most dominant.
Conclusions: The study underscores the importance of tailoring social media vaccine campaigns to address the autonomy needs of the target audience while considering trust-related issues to mitigate vaccine hesitancy. Emphasizing individual autonomy in vaccine decision-making processes can enhance engagement with pro-vaccine content, especially in older demographics.
Keywords: A/B split test; COVID-19; EPPM; Facebook; SDT; health campaign; vaccine.