Political Polarization During Disease Outbreaks: A Meta-Analysis of Archival Survey Data From Polio to COVID-19.

Objectives. To assess how political polarization during COVID-19 compares with that in past disease outbreaks in the United States. Methods. Using random-effects meta-analyses and mixed-effects meta-regressions, we searched the Roper Center for Public Opinion Research and estimated the association between polarization during COVID-19 and during non-COVID-19 disease outbreaks. Results. The study included 170 polls spanning 13 outbreaks over nearly 70 years. Polarization during COVID-19 was 5 and 12 times greater than in past disease outbreaks in terms of concern about infection and vaccine hesitancy, respectively. After we controlled for survey-level characteristics, COVID-19 was associated with 20.23 (95% confidence interval [CI] = 12.30, 28.17) and 25.89 (95% CI = 6.63, 45.16) additional percentage points of polarization regarding concern about infection and vaccine hesitancy, respectively-far higher than historical trends would predict. Conclusions. In terms of concern about infection and vaccine hesitancy, polarization during COVID-19 was substantially higher than in any other disease outbreak in modern American history for which we have relevant data. Public Health Implications. High levels of polarization do not appear endemic to disease outbreaks, suggesting such division may be preventable in the future. (Am J Public Health. Published online ahead of print August 28, 2025:e1-e13. https://doi.org/10.2105/AJPH.2025.308226).