Polarization and health-related behaviors and outcomes during the COVID-19 pandemic: a systematic review.

Objective Political and affective polarization are different, but related concepts, which can shape trust in authorities, interpretation of health messages, and health behaviors and outcomes. The aim of this study was to systematically review the research literature, exploring how affective and political polarization are associated with COVID-19-related health behaviors and outcomes.Methods From January 1, 2019 to November 27, 2024, we searched 12 electronic databases for studies about affective or political polarization and COVID-19-related outcomes, including preventive behaviors such as vaccination, compliance with policies, perceived risk and health outcomes. We included studies reporting primary data from participants of any age and gender, published in any language. Two independent reviewers, from a total of seven, conducted study selection, data extraction and risk of bias assessment. We synthesized findings narratively and reported them according to the PRISMA 2020 statement.Results Of 2021 unique articles, we included nine cross-sectional studies, all conducted in the United States of America or Europe from 2020 to 2022. Four studies found associations between higher political polarization and lower COVID-19 vaccine uptake or intent. Reported associations between vaccination and affective polarization were mixed. Four studies of other COVID-19 attitudes or prevention measures found mixed results for both types of polarization. In one study, no association was found between polarization and changes in death in 2020 compared with 2015 to 2019. The risk of selection bias in included studies was high.Discussion This systematic review found some evidence of associations between polarization and COVID-19 health-related behaviors and outcomes. Cohort studies are needed to understand the direction of association. More international and interdisciplinary approaches to the study of polarization are needed to generate evidence to inform health and public policy effectively and improve preparedness for future pandemics.