An experimental study on the effects of Electronic Medicinal Product Information on vaccine hesitancy

Although immunization through vaccination is one of the most successful public health interventions, actual coverage of vaccination program has decreased rapidly over the last years due to increased vaccine hesitancy. Cognitive biases have been shown to play an important role in affecting vaccine hesitancy. In this study, we conducted a randomized-control trial (N = 2000, N = 1000 from Spain and N = 1000 from Bulgaria), where subjects were randomly assigned to one condition. The conditions differed by whether an electronic Product Information (ePI) was presented to the subjects and by the type of information that was focused to the patient. The current study showed that the provision of digital information in the form of an ePI has important consequences for achieving high vaccination rates. The main result suggests that providing vaccination information in the form of an ePI can increase patients’ vaccine hesitancy. This effect remained when positive and/or negative information in the ePI was focused to the patients. Additionally, we observe that vaccine hesitant individuals spend less time reading the ePI. We conclude, by relating the current study to the relevant literature, that information overload could be the main driver of vaccine hesitancy in the context of this study.