I agree with Davey Smith and colleagues about the expression of certainty in covid-19 communications and the effects on trust and public beliefs. 1 Certainty is reassuring for the general population at times of crisis. Certainty around severity increases perceived susceptibility, and clarity on resulting required behaviours provides a sense of control. But with declining certainty, we erode that trust. This is diametrically opposed to our clinical model of shared decision making, which helps patients weigh up the pros and cons of difficult health trade-offs so that decisions are made through discussion of values, preferences, and different likely outcomes. Current communication around covid-19 has led to polarisation and dismissal of rival positions. The evidence base usually acts as an impartial referee in shared decision making, but, as the authors rightly point out, the evidence is uncertain for a disease in its infancy. The presentation of personally changed positions is a fitting end to the article.