Informing the public matters: A field experiment during an ongoing health crisis in Belgium

During an ongoing outbreak of Legionnaires' disease in Belgium, residents of the affected area took part in an online field experiment. The impact of four distinct crisis messages used by the Belgian authorities was tested on uncertainty, fear and trust. After receiving any of these messages, participants felt less insecure, less anxious and had more trust in the authorities as compared to before they saw the information. The extent of this positive impact of crisis information depended, however, on the message that was offered. Two messages offering comprehensive instructing and adjusting information appeared more effective than two messages offering only limited (predominantly adjusting) information. The use of visuals, by means of an infographic, did not seem to hinder or increase the effectiveness of the message in this particular study. Organizations and authorities responsible for managing a health crisis are recommended to actively communicate a complete overview of information about what is going on as well as specific information regarding what the public can (or cannot) do to address the matter. While visual aids may not be necessary, they can be helpful to effectively communicate a comprehensive overview of information through social media.