RESUMEN
Uncertainties pervade our health choices, particularly in the context of a novel pandemic. Despite this, rather little is known about when and how to effectively communicate these uncertainties. The focus in the medical literature so far has been on how patients respond to mentions of uncertainty relating to diagnosis or treatment, showing that these can have detrimental effects on trust and satisfaction. On the other hand, how patients are affected by these communications over time, particularly in the face of conflicting information, has received little attention. This is particularly important in the context a novel pandemic where uncertainty is rife and information changes over time. To fill this gap, we conducted an online study with UK participants on hypothetical communications relating to COVID-19 vaccines. Participants first read a vaccine announcement, which either communicated with certainty or uncertainty, and then received information which conflicted with the announcement. Those who were exposed to the certain announcement reported a greater loss of trust and vaccination intention than those who were exposed to the uncertain announcement. This shows that communicating with unwarranted certainty can backfire in the long-term, whereas communicating uncertainties can protect people from the negative impact of exposure to conflicting information.
