Positive emotions and credibility: Understanding how a community-engaged online campaign featuring clinician testimonials improved rural vaccine promotion.

During the COVID-19 pandemic, vaccine hesitancy emerged as a public health challenge in the U.S., particularly affecting rural communities. This study examined the effectiveness of a community-engaged campaign, Communities Confronting COVID-19 (C3), in promoting COVID-19 vaccines among rural residents. Using a single-session four-arm randomized survey experiment involving N = 1364 rural residents, this study provided empirical evidence for the effectiveness of featuring clinicians serving rural communities as vaccine ambassadors and utilizing their personal testimonials in a community-engaged campaign. Results showed that, compared to non-testimonial clinician videos, rural clinician testimonials were rated as more effective by rural audiences. Rural clinician testimonials were associated with higher positive emotions and subsequently showed positive indirect associations with Perceived Message Effectiveness, perceived social benefits of COVID-19 vaccines, and general vaccine confidence. Furthermore, compared to rural community leaders, rural clinicians were associated with higher perceived social benefits of COVID-19 vaccines. Rural clinicians were also rated with higher credibility as vaccine advocates, which in turn was associated with higher Perceived Message Effectiveness, perceived social benefits of the vaccines, and general vaccine confidence. Neither condition significantly reduced vaccine misbeliefs nor provoked reactance. These findings highlight the key indirect roles of positive emotions and messenger credibility in promoting COVID-19 vaccines and rebuilding general vaccine confidence, offering actionable design insights for evidence-based campaigns to support vaccine confidence in underserved rural populations.