A Role for News Media in Mass Polarization during the COVID-19 Pandemic

The extent to which media contributes to mass polarization remains an open question. We conducted a systematic, comprehensive, and longitudinal analysis of COVID-19 coverage on the websites and Twitter accounts of liberal, conservative, and centrist U.S. news media over the pandemic's first three years, examining over half a million news items from 31 outlets. We uncovered significant polarization in COVID-19 coverage closely aligned with the political biases of news media entities. Additionally, we revealed a striking reliance on politicized and out-group partisan cues in COVID-19 coverage by conservative-leaning media. Unexpectedly, conservative audiences on Twitter showed a growing preference for engaging with and retweeting COVID-19 news. These dissemination patterns strongly predicted mortality and vaccination rates across U.S. counties. Our findings suggest a central role for partisan and socio-psychological cues in mediating the causal link between media polarization, audience polarization, and the resultant polarized patterns of local COVID-19 outcomes throughout the pandemic.