The Effect of Framed Health Messages on Intention to Take Antivirals for Pandemic Influenza: A Vignette-Based Randomised Controlled Trial.

During the last influenza pandemic, adherence to antivirals was suboptimal. This study investigated the effect of manipulating the wording of written health messages on intentions to use antivirals as prophylaxis for pandemic influenza. After reading a hypothetical pandemic flu scenario, adult UK residents (N = 216) were randomly allocated to one of the four conditions, defined by a 2 × 2 (agency assignment × attribute framing) factorial design. Each condition presented messages describing the pandemic flu using linguistic expressions that assigned agency to either humans (HA: human agency) or the virus itself (VA: virus agency), whilst describing the antivirals side effects in terms of the chances of either experiencing (NF: negative framing) or not experiencing side effects (PF: positive framing). Intentions to use the antivirals and potential mediating factors were measured. Mean adherence intentions were high in all conditions with no significant differences between them. Higher perceived susceptibility, anticipated regret, self-efficacy, trust, and low response costs were found to predict adherence intentions. The VA messages increased perceived severity, the PF messages increased self-efficacy, whilst VA*PF affected response efficacy. The evidence did not support the hypothesis that the VA and PF framings can increase adherence intentions compared to the HA and NF messages, respectively.