[Evaluation of the Dunning Kruger effect in relation to vaccination: a study of messages on the social network LinkedIn.].

Objective: The Dunning-Kruger effect refers to an excess of confidence regarding one's abilities and knowledge; trust leads to transmitting information in an assertive manner, regardless of its validity or veracity, of experts, but of great impact on public opinion. This study evaluated the existence of the Dunning-Kruger effect in messages related to vaccination against COVID-19 on LinkedIn.

Methods: 448 messages were evaluated and the authors' knowledge and training on the subject were related. In the statistical treatment, the Chi-square test was performed to determine if there is a significant association between the variables, establishing the level of significance at P<0.05. These procedures were carried out using SPSS statistical software.

Results: 448 messages were analyzed. Of these, 153 reflected very high certainty, 115 medium certainty, 107 low certainty and 73 reflected doubts. The group that issued the most messages with absolute certainty (41.8%) was the group with minimal knowledge about COVID-19. Of this group without knowledge on the subject, only 7.1% expressed messages without expressing certainty. The group with very high knowledge on the subject was more likely to reflect uncertainty, communicating 15.7% of the messages with absolute certainty and 37.1% with zero certainty.

Conclusions: It is obtained that those people with less knowledge express their messages more assertively and present less acceptance of the COVID-19 vaccine in their speeches. The presence of the Dunning-Kruger effect in relation to COVID-19 vaccination is demonstrated.