One of the main factors driving differences in COVID-19 vaccination rates across the country is partisanship. Our surveys consistently find that Democrats are much more likely to report having been vaccinated than Republicans, and Republicans are much more likely to say that they definitely do not want to get vaccinated.  In May, just as vaccine supply was starting to outstrip demand, we examined average vaccination rates by county and found that rates were lower in counties that voted for Trump in the 2020 Presidential election compared to those that voted for Biden. Now, two months later, we find that not only does this remain the case, the gap has grown.

We obtained data on the share of the population fully vaccinated 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:  To create a longer time series, we also looked at vaccination rates in April 2021.

While the share of the total population that is fully vaccinated has increased for both county groups, it has increased faster in counties that voted for Biden, resulting in a widening gap.  Three months ago, as of April 22, the average vaccination rate in counties that voted for Trump was 20.6% compared to 22.8% in Biden counties, yielding a relatively small gap of 2.2 percentage points.  By May 11, the gap had increased to 6.5% and by July 6, 11.7%, with the average vaccination rate in Trump counties at 35% compared to 46.7% in Biden counties. See Figures 1 and 2.

Figure 1: Vaccination rates in counties that voted for Biden and counties that voted for Trump, April – July 2021

Figure 2: The gap in vaccination rates between counties that voted for Biden and counties that voted for Trump, April – July 2021

Although there has been an overall significant slow-down in COVID-19 vaccination rates in the U.S., these findings show a widening divide of communities at risk for COVID-19 along partisan lines. A key component of any effort to boost vaccination rates among Republicans will be identifying the right messengers. According to our Vaccine Monitor, which tracks the public’s attitudes and experiences with COVID-19 vaccinations, Republicans are most likely to trust their doctors and employers to provide reliable information on COVID-19 vaccines, while government sources are less trusted.  Going forward, efforts that focus on these messengers, including President Biden’s recent announcement to augment vaccination distribution through doctor’s offices, may help, but there is a hardcore group of vaccine resisters who are disproportionately Republican and will be difficult to move.

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