Free flu shots vs herd immunity in flu vaccination advertising : the interaction of attribute type and message sidedness on flu vaccination judgment

Purpose: This study aims to examine how the relative importance of a search versus a credence attribute, strategically addressed in a flu vaccination advertisement, varies as a function of message sidedness. A search attribute was designed to highlight the affordability of flu shots, and a credence attribute addressed the potential health benefits of flu vaccination. Design/methodology/approach: Two experiments were designed to explore how the relative persuasiveness of search versus credence attributes varies as a function of message sidedness in the context of flu vaccination advertising. In Experiment 1, the search–credence attribute type was manipulated by addressing either the affordability (e.g. “Get free flu shots”) or indirect health benefits of flu vaccines (e.g. “Improve herd immunity/community health”). In Experiment 2, an individual-level credence attribute (e.g. “Strengthen your immune system”) was created and compared to the other two attribute conditions used in Experiment 1: a search versus a societal credence versus an individual credence attribute. Findings: Experiment 1 (N = 114) revealed the relative advantage of a search attribute (free flu shots) in the two-sided persuasion. Experiment 2 (N = 193) indicated that the persuasive impact of a societal credence attribute (herd immunity/community health) was greater in the two-sided message condition (vs one-sided message condition). Originality/value: Relatively little research has examined how consumers respond to strategic flu prevention and vaccination messages promoting either credence or search attributes. Motivated by the need to investigate the relative effectiveness of stressing “herd immunity” versus “free flu shots” in flu vaccination advertising, this study examines how the effects of these distinct attributes on flu vaccination judgments differ between two-sided (e.g. “No vaccine is 100% effective”) and one-sided persuasion.