The Red/Blue Divide in COVID-19 Vaccination Rates Continues: An Update

Not only has COVID-19 vaccination divided along partisan lines, our polling has found that political partisanship is a stronger national predictor of vaccination than other demographic factors. Partisanship in vaccination rates has borne out at the county level. In our tracking of COVID-19 vaccination rates in counties that voted for Trump compared to counties that voted for Biden, we found a widening gap between April and September of last year.

This update examines vaccination rates since the vaccination effort began, and through January 11, 2022. It also looks at booster dose rates since December 15 (when such data first became available at the county level). It is based on analysis of data on the share of the population fully vaccinated and share of the fully vaccinated who have received a booster dose by county from the Centers for Disease Control and Prevention’s (CDC) COVID-19 Integrated County View and data on the 2020 Presidential election results by county from here (for more detailed methods, see: https://www.kff.org/coronavirus-covid-19/issue-brief/vaccination-is-local-covid-19-vaccination-rates-vary-by-county-and-key-characteristics/). We find that:

  • Biden counties continue to have higher COVID-19 vaccination rates than Trump counties. Although overall vaccination rates have risen over time, people living in Biden counties continue to be more likely to be fully vaccinated than those in Trump counties. As of January 11, 65% of those in Biden counties were fully vaccinated compared to 52% of those in Trump counties.
  • The gap between Biden and Trump counties has widened over time. The current gap of 13.2 percentage points between the share fully vaccinated in Biden counties versus Trump counties is the highest to date. The difference was about 12 percentage points in the last few months of 2021 and less than 9 percentage points last June.
  • There is no gap between Biden and Trump counties in the share of the fully vaccinated with booster doses. At the same time, the share of fully vaccinated individuals who have received a booster dose is the same (37%) in each group. Furthermore, the gap in booster rates between Biden and Trump counties has been very small since December 15, with the largest gap being a 1 percentage point difference. This could reflect a greater inclination on the part of those already vaccinated to get a booster shot, especially given the spread of the Omicron variant, as suggested by recent polling. The same poll found that the unvaccinated remained unmoved.
  • Still, given the underlying gap in vaccination rates, there is also a gap in the share who are boosted across the two groups, and that gap has been widening over time. On December 15, the share of those in Biden counties with boosters was 16% compared to 14% in Trump counties, a 2 percentage point difference. By January 11, it had widened to a 6 point difference, with 25% of those in Biden counties with boosters compared to 19% of those in Trump counties.

Vaccinations, and boosters in particular, have been shown to be effective in providing protection against COVID-19, including the Omicron variant. Lower levels of vaccination leave communities more vulnerable to severe illness, especially as cases are surging. In several states, data have demonstrated that hospitalizations and deaths are higher among unvaccinated individuals compared to those who are vaccinated, both during the earlier Delta wave and during the current Omicron surge. The ongoing disparity in vaccination rates across Biden and Trump counties continues to put some communities at greater risk of more severe COVID-19 disease.

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Filling the need for trusted information on national health issues, the Kaiser Family Foundation is a nonprofit organization based in San Francisco, California.