How Communicating Vaccine Benefits and Harms in Fact Boxes Affects Risk Perceptions

Abstract: Background: A fact box is a promising tool for benefit-risk communication. This compact table summarizes the benefits and harms of a health-related intervention and compares the intervention to a control group. Although previous research has demonstrated that fact boxes are well understood, little is known about how they affect risk perceptions. Risk perception is particularly relevant to vaccination behavior. Aims: Two experiments investigated how different profiles of vaccine benefits and harms influence risk perceptions and the intention to vaccinate. Method: In Experiment 1, 430 participants were included in a 4 (benefits [vaccine effectiveness]) × 2 (harms [probability of vaccine adverse events]) between-subjects design. In Experiment 2, 541 participants were included in a 2 (benefits) × 2 (harms) × 2 (comprehension test conducted before or after assessment of risk perceptions) between-subjects design. Measures: Perceived risk of vaccination, intention to vaccinate, comprehension, and, in Experiment 2 only, perceived risk of non-vaccination. Results: Greater benefits decreased the perceived risk of vaccination and increased the intention to vaccinate. More harms increased the perceived risk of vaccination and, in Experiment 2 only, decreased the intention to vaccinate. More benefits increased the perceived risk of non-vaccination. Exploratory analyses showed that the comprehension and position of a comprehension test influenced risk perceptions. Limitations: The experiments used MTurk convenience samples and a fictitious disease. Conclusion: Communicating vaccine profiles in fact boxes affects risk perceptions. Additional measures may cue a deeper elaboration of the vaccine profile.