Vaccine hesitancy, refusal, Covid-19 and cognitive bias: a narrative review

ABSTRACT

Context. Vaccine hesitancy, defined as "delaying or refusing safe vaccination despite its availability", has been classified as one of the 10 health threats by WHO. The main reasons for vaccine hesitancy in Covid-19 are the dangerousness of the vaccine, the opposition to vaccination in general, and a virus that is considered not very dangerous. Errors resulting from subconscious mental procedures of information processing, called cognitive biases, participate in the decision to be vaccinated. Objective. The objective of this work was to describe the cognitive biases that may participate in vaccine hesitation in Covid-19 and its refusal. Methods. Narrative review of the literature according to PRISMA criteria, from 2011 to 2021 on Medline((R)) and Cairn((R)), and from references. Results. Ten reviews or position papers were selected. Availability bias (media coverage of an adverse event), representativeness bias (stereotype rather than statistical), attribution bias (anecdotal observation and causality) may participate in the judgment of vaccine dangerousness. Ambiguity aversion, omission and present bias may partly explain the inaction choice of some health care users. Distancing from power leads to distrust of public authorities. This feeling of inequality contributes to the opposition to vaccination in general. The biases of naturalness (natural immunization) and optimism contribute to the judgment of a virus that is not very dangerous. Conclusion. Motivational interviewing of patients with vaccine hesitation or refusal can be facilitated by the knowledge of these biases.