Ask any physicist, they will tell you.
The narrower the aperture, the wider the displacement.
A counterintuitive notion derived from the classic experiment in which light was directed to pass through slits of varying widths.
The study found that the narrower the width of the slit the light passed through, the wider the displacement of light subsequent to passing through it. And that slight differences in the width produce notable differences in the spread of the light.
For physicists, the magnified effects of the light’s spread relative to minute differences in the slit’s width come as no surprise. They understand this principle.
Health policy experts, however, seem unable to understand this principle – explaining why so many experts were surprised to see COVID-19 vaccine disparities increase as eligibility expanded. That what many policy experts perceived as healthcare equity – increasing access to vaccines – actually increased disparity.
A counterintuitive notion largely predicated on the erroneous belief that all patients behave the same, that by increasing vaccine availability, every patient will now be more likely receive the vaccine.
Something we know not to be true, particularly among chronic diseases. We know that among diabetic patients, there are very real differences in how each patient responds – some are proactive with diet and exercise, while others need constant reminders to stick to their diet.
Differences not immediately apparent, which only appear after a patient exhibits those tendencies, seen in the resulting effects from those tendencies. A frustrating, but all too common conundrum many physicians face.
The nuanced tendencies many patients exhibit – tendencies that determine who is compliant and who is not are like the width of the slit – are hardly noticeable to the average person.
But these minute variations produce profound differences in overall patient behavior. Differences that have manifested as stark disparities in vaccine coverage.
Something those of us following vaccination rates throughout the pandemic have known, in broad general terms. The CDC has released multiple reports over the past few months highlighting the racial disparities in vaccine coverage. We know Black patients receive the vaccine less than average and are disproportionately affected more than the average population.
But a more granular analysis of the data reveals unique trends in how these disparities form – disparities that vary locally, state by state, revealing nuanced tendencies that are determined locally rather than broadly defined racially.
An analysis by the Kaiser Family Foundation found that the share of vaccinations received by Black people continues to be smaller than the share of deaths in most states. Conversely, the share of vaccinations received by Hispanic people is similar to or higher than the share of deaths in most states. Diverging trends that appear broadly across the nation, providing the pretense of a racial disparity, that, upon closer state by state examination, are less clearly demarcated.
For example, in Colorado, 11% of vaccinations have gone to Hispanic people, while they account for 41% of cases, 25% of deaths, and 22% of the total population in the state. Similarly, in the District of Columbia, Black people have received 40% of vaccinations, while they make up 55% of cases, 70% of deaths, and 46% of the total population.
A granular examination reveal vast differences across states, differences that grow more pronounced as the population of minorities increase. Which are not seen in states with smaller minority populations.
For example, in Oregon, 2% of vaccinations have been received by Black people, similar to their share of cases, 3%, deaths, 2%, and the total population, 2%. In Alabama, 5% of vaccinations have been received by Hispanic people, which is higher than their share of deaths 2% and similar to their share of cases 5% and their total population share 4%.
The more easily digestible patterns, in which vaccinations rates, death rates, and case loads are all symmetric only hold true in states that have smaller shares of Hispanic and Black residents. But these trends diverge in states with larger minority populations – in ways uniquely localized and specific to each state, with no consistent pattern of change.
For example, in May 2021, as the pace of vaccination rates increased overall, the rate of growth varied across minority populations, as rates increased by 1.5% for White people, from 41.6% to 43.1%, and by 1.3% for Black people, from 27.8% to 29.1%, and by 1.9% from 30.4% to 32.3% for Hispanic people, and by 2.2%, from 52.1% to 54.3% for Asian people.
Minute differences that once aggregated over the course of months produce notable disparities in vaccination rates among minority populations.
Producing trends that are simultaneously national and localized, predictable and irrational – in other words, complex.
And with all things complex, are often misunderstood. This is why something like vaccine access, a perceived type of healthcare equity, actually manifests as worsening healthcare disparity. The disparity is in the patterns of dispersion, defined by the width of the slit.
Minor differences hardly noticeable at first that then come to determine overall vaccination rates, and consequently, overall patient outcomes.
Perhaps we should start to focus on the width of the slit instead of the patterns of displacement – so we are not fooled by healthcare disparity masquerading as healthcare equity.
Per capita national health expenditures from 1960-2020
The data categorizes expenditures as national health expenditures, health consumption costs, personal health costs, administrative costs, and public health activities cost.
Source: Centers for Medicare & Medicaid Services, Office of the Actuary, National Health Statistics Group; U.S. Department of Commerce, Bureau of Economic Analysis; and U.S. Bureau of the Census.