Facebook Comments Influence Perceptions of Journalistic Bias: Testing Hostile Media Bias in the COVID-19 Social Media Environment

News organizations increasingly use Facebook to expand their reach and foster audience engagement. However, this free platform exposes news audiences to user comments before accessing and reading news articles. This exposure shapes the visible opinion climate and has the potential to influence readers. Through the application of the hostile media bias hypothesis, the influence of Facebook comments on COVID-19 related news articles and a knowledge-based assessment on perceptions of news bias and credibility are tested using a nationwide sample of Facebook users (N = 450). Findings show that user comments enhance negative perceptions of bias and diminish perceptions of favorability. The ability for knowledge-based assessments to alleviate this negative influence may induce reactance and needs further investigation.