Introducing the New COVID-19 Vaccine Coverage Index

The United States is racing against time to vaccinate a majority of the population, while also dealing with supply- and demand-related barriers that can jeopardize any phase of the vaccine rollout. That’s why today, we launched a new data tool, the U.S. COVID-19 Vaccine Coverage Index (CVAC), to provide health officials and policymakers the precise, county-level data they will need to identify which communities are at risk of low COVID-19 vaccine coverage and why, based on underlying community characteristics.

The new index assesses every county in the United States — geographically and demographically — to identify the barriers to getting their residents vaccinated quickly, safely, and equitably.

Top COVID-19 vaccine coverage barriers

The index captures five key themes — Historic undervaccination, Sociodemographic barriers, Resource-constrained health systems, Healthcare accessibility barriers, and Irregular care-seeking behaviors — and ranks every county on a scale from 0 (lowest level of concern) to 1 (highest level of concern). Level of concern is categorized into: very low concern (score of 0–0.2); low concern (0.2–0.4); moderate concern (0.4–0.6); high concern (0.6–0.8), and very high concern (0.8–1).

Essentially, we created this index to help decision makers address the where, the why, and the how of our current COVID vaccine challenge: Where are the communities that are most at risk for low vaccine coverage? Why are these communities at risk? And how do we accelerate coverage?

Key Index Findings

In addition to the Index, we released an analysis of the current state of the COVID-19 vaccine rollout across American communities, which centered upon four key findings:

Finding 1: More than half — 54% — of all U.S. counties score “very high” on at least one barrier to achieving widespread vaccine coverage, with the South and the West most vulnerable to low vaccine coverage.

Finding 2: Each U.S. community faces its own unique set of barriers to achieving widespread vaccine coverage. For example:

  • Historic undervaccination is of concern in both rural and urban areas, with the West disproportionately affected. Hispanic and Native American communities are more likely to live in areas of high concern.
  • Sociodemographic barriers affect the South and small counties across regions. Rural Americans are five times more likely to live in areas of very high concern than urban Americans.
  • Resource-constrained health systems are of concern in rural areas and the South and Midwest. Hispanic, Native American, and rural Black populations are more likely to live in areas of high concern.
  • Healthcare accessibility barriers affect rural areas and communities in the South, with Native American, Black, and Hispanic populations more likely to live in areas of high concern.
  • Irregular care-seeking behavior disproportionately impacts the West, with many large, urban counties of high concern. Native American, Hispanic, Asian and rural Black populations are more likely to live in communities of very high concern.

Finding 3: During this first phase of the COVID-19 vaccine rollout, the states and counties with “Resource-constrained health systems” are falling behind. As vaccination eligibility expands and more priority groups are called upon, we should expect even starker differences in performance between regions if early action is not taken. For example:

  • Alabama has vaccinated the lowest proportion of its population of any state to date: to overcome its weaknesses in ensuring equitable access to healthcare, it should target its vaccination messaging and facilities to underserved communities.
  • West Virginia is one of the most successful states, thanks to a statewide interagency task force ensuring a uniform, coordinated response; but the next phases of vaccine rollout could be challenging in rural and socioeconomically disadvantaged areas.
  • Florida’s rollout is particularly slow in regions with irregular care-seeking behaviors. A concerted effort to reach those outside of the care system and those facing economic and transportation barriers to vaccination is critical.

Finding 4: Web searches about accessing the COVID-19 vaccine signal advance demand, and suggest lower demand for getting vaccinated in states with a poorer track record of historic vaccination and greater share of people without a regular point of care.

U.S. States and Counties of Highest Concern

According to the Index, the following sets of states and counties are of highest- and lowest concern when it comes to ensuring widespread vaccine coverage.

Interactive map representing the level of concern for COVID-19 vaccine coverage across U.S. counties


  1. Nevada
  2. Mississippi
  3. Oklahoma
  4. Texas
  5. Georgia
  6. Arizona
  7. Arkansas
  8. Indiana
  9. Florida
  10. Tennessee


  1. Connecticut
  2. Massachusetts
  3. New Hampshire
  4. Rhode Island
  5. Iowa
  6. District of Columbia
  7. Maryland
  8. North Dakota
  9. New Jersey
  10. Virginia


  1. Hidalgo County, TX (0.99) [855K]
  2. El Paso County, TX (0.96) [836K]
  3. Clark County, NV (0.92) [2.2 mill]
  4. Bexar County, TX (0.87) [2 mill]
  5. Polk County, FL (0.87) [686K]
  6. Pinal County, AZ (0.87) [433K]
  7. Pima County, AZ (0.86) [1 mill]
  8. Dallas County, TX (0.83) [2.6 mill]
  9. Miami-Dade County, FL (0.82) [2.7 mill]
  10. Kern County, CA (0.82) [888K]


  1. Apache County, AZ (1.0) [72K]
  2. Navajo County, AZ (1.0) [109K]
  3. Tallahatchie County, MS (1.0) [14K]
  4. Maverick County, TX (1.0) [58K]
  5. Jim Hogg County, TX (1.0) [5K]
  6. Scott County, MS (1.0) [28K]
  7. Culberson County, TX (1.0) [2K]
  8. Starr County, TX (1.0) [64K]
  9. Zavala County, TX (1.0) [12K]
  10. Duval County, TX (1.0) [11K]

Community Challenges the Index Can Help Solve

To help guide resource allocation, response plans, and advocacy, we have compiled a list of action-oriented solutions for addressing high scores in each of the five CVAC themes. These are not prescriptive solutions, but a starting point for local leaders to see how they can use this index to design an informed, precise strategy at any phase of their vaccine planning and rollout.

Explore the new COVID-19 Vaccine Coverage Index here.

We use all the tools available from behavioral science, data science, and artificial intelligence to unlock solutions that will save and improve people’s lives.

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