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As the COVID-19 pandemic ravaged the country, it shone a spotlight on a relationship which many already knew to be true.

“Health and place are intricately linked,” said Harald Schmidt, assistant professor of Medical Ethics and Health Policy at the University of Pennsylvania.

Across the country, communities with greater COVID-19 incidence and mortality are often those with the most significant vulnerabilities. Schmidt noted that this underscores “targeting COVID vaccines to more disadvantaged areas is good for equity and disease control.”

This relationship is not unique to COVID-19; there have been health disparities associated with socio-environmental factors since before the 1918 influenza pandemic. But only in the last several decades, have states used disadvantage indices, such as the CDC’s Social Vulnerability Index (SVI) and the Area Deprivation Index (ADI), to help describe this relationship between health and place. A composite measure linked to a geographic location, these indices combine data on income, race and ethnicity, housing, access to health care, transportation, and other sociodemographic factors to provide a relative understanding of the vulnerabilities of residents living in that area. Past uses of SVI and ADI include assisting public health officials and local planners prepare for and respond to emergency events like hurricanes, disease outbreaks, or exposure to dangerous chemicals, as well as identifying communities that may need continued support to recover from such disasters. Schmidt emphasized the value of these statistical tools, noting that they “can help us compare different areas in ways that directly matter for public health.”  

Many states are addressing these disparities in their COVID-19 response efforts by allocating a greater share of vaccines to their most vulnerable communities in an effort to prioritize health equity. More often than not, state policymakers accomplish this task by using disadvantage indices to define and prioritize at-risk groups and effectively tailor allocation of and communications related to COVID-19 testing and vaccine distribution. In a recently published issue brief and webinar, AcademyHealth, with support from Blue Shield of California Foundation, examined states’ widespread adoption of disadvantage indices to prioritize health equity in their COVID-19 response.

While disadvantage indices are increasingly recognized as a valuable tool to help promote health and prioritize equity, we still have a lot to learn about their optimal use and potential drawbacks. Certain steps must be taken for these measures to tackle public health challenges beyond COVID-19.

Investments in data infrastructure must be made

In order for disadvantage indices to be effective in reducing health inequities, the data must be reliable. Given that race and ethnicity data is often missing or has other quality concerns, there is a critical need for investments in social determinants of health data infrastructure. Additionally, data granularity should accurately reflect the variability of the communities it describes.

“One major difference among widely used indices is [the scale of] the geographic area they center on,” said Schmidt, who spoke on the AcademyHealth webinar.

Some, such as the ADI, use block group level data (600 to 1200 people), while others, including the widely used SVI, use census tract data (1200 to 8000 people). Particularly in urban areas, where community resources might change from neighborhood to neighborhood, census tract data could fail to reflect the specific community needs and barriers experienced by the people who live there. However, Schmidt pointed out that “it is much harder to integrate data at the block group level […] so, there are tradeoffs between accuracy and feasibility.” This calls for investments in data infrastructure and capacity that will improve accuracy and accessibility of granular-level data to researchers and policymakers.

Indices alone are not enough; they must be partnered with legislation and community leadership

Although important, addressing disparate outcomes when responding to public health crises does not go far enough to ensure that health disparities are eliminated in a sustainable way. Disadvantage indices can be used to focus lawmakers’ attention on addressing root causes of health disparities, in addition to immediate needs. By identifying communities that experience significant barriers to health and well-being, disadvantage indices can be used to look at the laws and policies that impact that community and how they might perpetuate systemic racism and other structural barriers.

Local community leaders and community-based organizations must co-lead these conversations as well. Community partnerships, such as this Bay Area coalition formed to provide high-risk populations with COVID-19 testing, vaccination, and other essential services, can both represent the true needs of the community and serve as the bridge between that community and larger city, state, or federal bodies.

Although preliminary results are positive, further evaluation is necessary to inform future use

Although early experiences suggest that use of disadvantage indices in COVID-19 response efforts have been effective in mitigating exacerbation of existing health inequities, they are largely anecdotal and no large-scale evaluation of their impact on equity exists. There is also a wide variety of indices and each “differs in how it conceptualizes which areas are deemed disadvantaged,” said Schmidt.

Evaluations might also be helpful in assessing public and policymaker acceptability of the indices which, according to Schmidt, “can matter just as much for making a difference in improving public health and health equity on the ground.”

Sharing information is crucial to developing more robust indices and best practices

Many states that integrated disadvantage indices into their vaccine distribution plans opted for the CDC’s SVI, citing the ease of use, publicly available instructions, and CDC notoriety as driving factors. Providing open-source information about how to use indices and integrate them into resource allocation in areas related to COVID-19 and beyond may encourage further adoption. Additionally, as with many newly adopted policy devices, shared learning networks are valuable in communicating challenges, successes, and best practices of use. Networks like AcademyHealth’s State-University Partnership Learning Network and Medicaid Medical Directors Network provide an example of how facilitation of peer-to-peer learning advances knowledge capacity.

Use of disadvantage indices should not be limited to COVID-19

Looking ahead, there may be opportunities to use these tools in other public health areas beyond disaster preparedness and response. Schmidt highlighted a few of these, explaining how SVI could be mapped to “heat indices to ensure tailored access to cooling stations” or to look at “density of primary care providers to address gaps in access.”

There is a unique window of opportunity at the state and federal level where policymakers and funders’ attentions are focused on eliminating health disparities. Like Schmidt, many recognize the value that indices can have towards addressing these inequities. If policymakers wish to expand use of disadvantage indices in a feasible way, now is the time to make the necessary investments and partnerships before the window closes.

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Rachel Campbell-Baier

Research Associate - Mathematica

Rachel is currently a Health Research Associate based out of Mathematica’s DC office. Prior to starting at Mat... Read Bio

Caitlin Otter

Former Research Assistant - AcademyHealth

Caitlin Otter is former a Research Assistant at AcademyHealth, where she supported the Evidence-Informed State... Read Bio

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