Tipping the Fencesitters-The Impact of a Minimal Intervention Enhanced with Biological Facts on Swiss Student Teachers' Perception of HPV Vaccination Safety.

Not much is known about the role of scientific knowledge in vaccination decision making. This study is based on previous findings that the concern about the human papillomavirus (HPV) agent mutating back to a virulent HPV was common among Swiss student teachers and turned out to be one factor of vaccine hesitancy. The study investigate the impact of a standard public health brochure describing the effectiveness, safety, and importance of HPV vaccination on young student teachers, and the additional effect of supplementing the standard brochure with biological arguments against the mutation concerns. It uses a pre-posttest design and assigns participants randomly to two groups, one reviewing a standard public health brochure, the other the same brochure enhanced with additional biological information. Participants in both groups showed a significant positive change in their beliefs about vaccination safety, effectiveness, and importance in preventing cervical cancer. Post hoc analysis showed significant safety beliefs gain for the subgroup of participants who received the biology-enhanced text and held moderate, rather than high or low, pretest safety beliefs-the so-called fencesitters. We conclude that these fencesitters may particularly profit from even minimal (biologically supplemented) interventions, an effect that should receive more attention in future research.