Preferences for Social Media Vaccination Messaging.

Importance: Social media is a dominant source of health information, including vaccine information, but little is known about which message characteristics audiences prefer when deciding what social media content to engage with and about how to measure these preferences. Objective: To quantify the attributes of existing social media vaccination posts that are associated with the preference for and confidence in vaccination-related content. Design, Setting, and Participants: This cross-sectional study used a combination of the discrete choice experiment (DCE) and the Swiss tournament approaches to evaluate preferences, which were collected in an online survey between March and May 2024. Participants (aged ≥18 years) from a previous California-based COVID-19 study were recontacted through social media between January and August 2024. Participants completed the DCE and Swiss tournament test. Exposures: Participants viewed pairs of vaccination-related social media posts that varied systematically by attributes, such as messenger, source, tone, artwork type, age group of messenger, and topic. Main Outcomes and Measures: Participants selected which post they were most likely to engage with (like, share, or comment). Preferences were analyzed using a conditional logit model to estimate relative importance of post attributes. Results: Among 243 participants (mean [SD] age, 36.4 [12.4] years; 127 males [52.5%]), 153 (63.0%) reported favorable attitudes toward vaccines in general, 167 (68.7%) toward influenza vaccines, and 117 (48.2%) toward COVID-19 vaccines. Daily social media use was common (228 [93.8%]), and most participants preferred visual content, such as pictures (206 [84.8%]) or short videos (184 [75.7%]). In the DCE, social media vaccination posts from public health agencies such as California Department of Public Health (adjusted odds ratio [AOR], 1.80; 95% CI, 1.57-2.07) and University of California San Francisco (AOR, 1.67; 95% CI, 1.21-2.29) and posts depicting health care workers (AOR, 1.28; 95% CI, 1.12-1.47) or older adults (AOR, 1.48; 95% CI, 1.22-1.80) were more likely to be preferred. Humorous tone was associated with reduced preference (AOR, 0.45; 95% CI, 0.36-0.57), whereas COVID-19 (AOR, 2.35; 95% CI, 1.95-2.87) and influenza (AOR, 1.78; 95% CI, 1.54-2.06) topics were associated with increased likelihood for preference. Artwork type showed no significant association with preference. Conclusions and Relevance: This cross-sectional study found that participants preferred social media-based vaccination posts that were factual, featured health care professionals, and were sourced from public health organizations. Understanding communication preferences through innovative experimental methods can inform the design of digital public health communications.