Reexamining Health Messages in the Digital Age: A Fresh Look at Source Credibility Effects

This article investigates the influence of perceived source credibility on the effectiveness of health-related public service announcements (PSAs) and electronic word-of-mouth (eWOM) communications. Findings indicate that online commenters who are perceived to be credible are instrumental in influencing consumers’ responses to pro- versus antivaccination online PSAs. Results further suggest it is not the advertising message (i.e., the PSA-advocated position) alone that influences consumers’ responses (even when consumers perceive the PSA sponsor to be highly credible) but rather the commenters’ reactions to the claims presented in the PSA that also independently contribute to consumers’ vaccination attitudes and behavioral intentions. Finally, results also show that when the relevant expertise of online commenters is identified, the effectiveness of the PSA's advertising message is moderated by the interactive effect of the online comments and their associated perceived credibility.