[Enlightenment through official vaccination communication: an experimental study comparing evidence-based fact boxes with nudges and advertising].

Introduction: Evidence-based health information is a key tool in health communication to support informed decision-making. In contrast, there are behavioural approaches. The suitability of the different approaches seems to depend on the initial willingness to vaccinate and the information needs (e.g. of undecided people, sceptics).

Methods: Using the longitudinal Corona Online Opinion Panel Survey Special (COMPASS) survey panel, we conducted a preregistered experiment (N = 2944) in May 2021 involving information presentations on vaccination: evidence-based tabular and graphical fact box vs. norm and moral nudge vs. vaccination advertising. Before and after vaccination education, vaccination intentions, understanding of vaccination, and attitudes toward and trust in vaccines were measured among those willing, inclined, sceptical, opposed and undecided.

Results: Fact boxes supported understanding of vaccination. Graphical fact boxes reinforced vaccination intention of undecideds without information needs. The moral nudge, but not the norm nudge, increased the vaccination intention of vaccination sceptics and undecided people without information needs. No negative influence on trust in vaccines could be identified.

Discussion: Evidence-based information does not counteract the social goal of high immunisation coverage of the population. Depending on the intention to vaccinate and the need for information, different target groups react differently to vaccination communication. Questions of ethical and legal responsibility should be discussed with regard to nudging and vaccination advertising.