As of April 25, 2021, a total of 228,661,408 COVID-19 vaccination doses have been administered in the United States (US).  As more and more people became eligible for the vaccine, the number of total doses administered per day has been on an upwards trend.  However, the US still has a ways to go before reaching herd immunity. Currently, 42.2% of the total US population have received at least one dose and 28.5% are fully vaccinated.  Yet the seven day moving average of the number of total doses administered per day has been decreasing since April 12, 2021 (Figure 1).
Figure 1. Daily Count of Total Doses Administered and Reported to the CDC by Date Administered in the United States, April 25, 2021. 
While this particular decrease could be attributed to the pause in the use of Johnson & Johnson’s vaccine, the numbers had already begun fluctuating since the beginning of April 2021 (Figure 1). In addition, state-level data is showing that some regions are already exhibiting signs of decreased vaccine demand (Figure 2).
Figure 2. Percent of Vaccine Supply Used by State, April 26, 2021. 
Data from the Bloomberg COVID-19 Tracker as well as the CDC show that Mississippi and Alabama have the lowest percentage of vaccine supply used at 63.9% and 62.6%.  With increasing concerns about the spread of COVID-19 variants, it is imperative that we identify the factors behind this vaccination lag in order to reach herd immunity and minimize the risk of future outbreaks.
The Many Facets of Vaccine Hesitancy
One big issue that may be causing the drop in vaccination rates is vaccine hesitancy. This sentiment encompasses several different populations who each have their own reasons for not lining up for their shots. Contextualizing what vaccine hesitancy represents for each population is vital to developing effective targeted strategies.
We have previously mentioned vaccine hesitancy among African Americans in our blog post, Health Equity Issues Around Vaccine Hesitancy, and among healthcare workers in our LinkedIn post. [4,5] The hesitancy among African Americans centered round racial distrust while the healthcare workers were concerned with ethical issues. However, vaccine hesitancy is not exclusive even to these two groups.
The states that tend to have lower percentages of vaccine supply usage were generally also ones that voted Republican in the 2020 election (Figure 2). This observation lines up with survey results regarding vaccine hesitancy. The Monmouth University poll found that 43% of Republicans versus just 5% of Democrats said that they want to avoid the vaccine altogether.  The Quinnipiac University poll found that 45% of Republicans said that they do not plan to receive a COVID-19 vaccine.  Both of these surveys were conducted before public health officials called for a pause on the Johnson & Johnson vaccine. Data from the US Department of Health and Human Services also suggests that politically right-leaning regions also experienced a higher percentage of vaccine hesitancy (Figure 3).
Figure 3. Estimated Percentage of Adults in the US Who Are Hesitant to Get the COVID-19 Vaccine by County, March 2021. 
The Consequences of Partisanship
The political divide is even more stark at the city level. Charlottesville and Lynchburg are two Virginia cities located only an hour’s drive away from each other. Charlottesville is a mostly Democratic area and vaccine appointments are hard to come by even with two mass vaccination sites nearby. In contrast, vaccine appointments at a TJ Maxx mass vaccination clinic in Republican Lynchburg were plentiful.  When combined with the fact that 51% of Charlottesville’s population has received at least one dose compared to Lynchburg’s 32%, Lynchburg’s low vaccination rate is a cause for concern. 
The situation in Lynchburg is replicated in many different regions across the nation. These pockets of unvaccinated populations can lead to future outbreaks and may even allow chances for the coronavirus to mutate. While public health officials can redistribute vaccines in order to better accommodate differences in supply and demand, hesitancy remains a major roadblock in a race between vaccinations and COVID-19 mutations.
Governments play a central role in combating pandemics. A study conducted by Grossman et al. found that governors’ communications encouraging residents to stay at home were associated with a significant reduction in mobility in their states. In particular, communications from Republican governors were especially effective because they were seen as not conforming with their party affiliation.  With vaccine attitudes divided so closely along party lines, perhaps the most compelling strategy to boost vaccination rates is to have government leaders present a united front in terms of the COVID-19 vaccine’s effectiveness.
By Carissa S Kwan, Public Health Analyst, HSR.health
Centers for Disease Control and Prevention. (n.d.). COVID-19 Vaccinations in the United States. COVID Data Tracker. https://covid.cdc.gov/covid-data-tracker/#vaccinations. (Last Accessed: 4/26/2021)
Centers for Disease Control and Prevention. (n.d.). Trends in Number of COVID-19 Vaccinations in the US. COVID Data Tracker. https://covid.cdc.gov/covid-data-tracker/#vaccination-trends. (Last Accessed: 4/26/2021)
Bloomberg. (n.d.). More Than 1.06 Billion Shots Given: Covid-19 Tracker. Bloomberg. https://www.bloomberg.com/graphics/covid-vaccine-tracker-global-distribution/. (Last Accessed: 4/26/2021)
Kwan, C., & Meena, L. (2021, April 12). Health Equity Issues around Vaccine Hesitancy [web log]. https://hsr.health/2021/04/12/black-lives-matter-but-dont-ask-covid/.
Kwan, C. (2021, April 20). HSR.health on LinkedIn: Ashamed to Be Vaccinated? The Ethics of Health Care Employees Forgoing. LinkedIn. https://www.linkedin.com/feed/update/urn:li:activity:6790239700763348992.
Murray, P. (2021, April 14). NATIONAL: ONE IN FIVE STILL SHUN VACCINE. West Long Branch; Monmouth University. https://www.monmouth.edu/polling-institute/documents/monmouthpoll_us_041421.pdf/
Quinnipiac University. (2021, April 14). QU Poll Release Detail. Quinnipiac University Poll. https://poll.qu.edu/national/release-detail?ReleaseID=3695.
Ivory, D., Leatherby, L., & Gebeloff, R. (2021, April 17). Least Vaccinated U.S. Counties Have Something in Common: Trump Voters. The New York Times. https://www.nytimes.com/interactive/2021/04/17/us/vaccine-hesitancy-politics.html?smtyp=cur&smid=fb-nytimes&fbclid=IwAR0zvAN7CN4FYTQcYOSN8HuSjkdd_yQQuqXHFQ_BzZYWht91xsl2Dcb961Y.
Edney, A., & Armstrong, D. (2021, April 15). Unused Vaccines Are Piling Up Across U.S. as Some Regions Resist. Bloomberg News. https://www.bloomberg.com/news/articles/2021-04-15/unused-vaccines-are-piling-up-across-u-s-as-some-regions-resist.
Virginia Department of Health. (n.d.). COVID-19 Vaccine Demographics. Virginia Department of Health. https://www.vdh.virginia.gov/coronavirus/covid-19-vaccine-demographics/. (Last Accessed: 4/27/2021)
Grossman, G., Kim, S., Rexer, J. M., & Thirumurthy, H. (2020). Political partisanship influences behavioral responses to governors’ recommendations for COVID-19 prevention in the United States. Proceedings of the National Academy of Sciences, 117(39), 24144–24153. https://doi.org/10.1073/pnas.2007835117