Confirmed cases of COVID-19 are most prevalent in wealthy and white communities

First off, this is a story about who is getting tested, not about which communities actually have the highest numbers of individuals with the novel coronavirus.

In southern California, Los Angeles County’s and Orange County’s health agencies have been releasing the number of confirmed COVID-19 cases on a city by city basis. I took the data and analyzed it against certain demographic categories from US Census data from 2018 to see what could be learned from this data regarding the differences in populations.

Scatter plot showing increasing rate of confirmed COVID-19 cases with increasing city median income, r²=0.2227

A fairly clear increasing trend is revealed when confirmed COVID-19 cases are plotted against the median income of the city. More wealthy communities tend to have a higher rate of confirmed COVID-19 cases.

A bar graph displaying seven tranches of median household income and increasing rate of COVID-19 with increasing income
A bar graph displaying seven tranches of median household income and increasing rate of COVID-19 with increasing income

Cities with median household income above $110,000 per year have a confirmed COVID-19 case rate more than three-and-a-half times the rate in cities where the median household income is below $50,000 per year. While it is possible that there is something about wealthier cities that makes their citizens more likely to have the coronavirus, it is more likely that the data is showing that residents of wealthy cities have more access to coronavirus testing than residents of poorer cities.

Scatter plot showing the COVID-19 case rate of a city against the percentage of city residents over age 65.
Scatter plot showing the COVID-19 case rate of a city against the percentage of city residents over age 65.

The confirmed COVID-19 case rate is positively correlated with the percentage of a city’s residents over the age of 65. This is reasonable, as coronavirus tests have been restricted to high-risk individuals, a category that includes the elderly. However, the correlation is weaker (R²=0.08) than that of median household income (R²=0.22).

A scatter plot showing confirmed COVID-19 case rate versus the percentage of a city’s residents without health insurance.
A scatter plot showing confirmed COVID-19 case rate versus the percentage of a city’s residents without health insurance.

A stronger correlation (R²=0.11) is revealed when the confirmed COVID-19 case rate is plotted against a city’s uninsured population. The higher the percentage of uninsured within a community, the lower the rate of confirmed COVID-19 cases.

For cities where fewer than 6% of people lack health insurance, the rate of confirmed COVID-19 cases is three times higher than the rate found in cities where greater than 16% of the population lack health insurance. Where more people have the financial means to acquire a coronavirus test, more positive test results are found.

Some have suggested that urban density is playing a role in the coronavirus outbreak; that the more dense a community is, the more people interact with each other, and the higher likelihood of acquiring a communicable disease. But the data from Los Angeles County and Orange County does not show evidence of this theory.

There is almost no correlation (R²=0.00) between the density of a city and the rate of confirmed COVID-19 cases.

Some nativists have suggested that the outbreak has something to do with the numbers of foreigners in a community, and some racists are blaming it on Asians. However, data from Los Angeles County and Orange County shows a negative relationship between a city’s foreign-born population and confirmed COVID-19 cases. The higher the composition of foreign-born people in a city, the lower the rate of confirmed COVID-19 cases (R²=0.09).

The correlation is also negative when comparing a city’s Asian population with the confirmed COVID-19 case rate, though the correlation is much weaker (R²=0.03).

There is one racial group where the correlation is quite apparent: white people.

The more white people compose a city’s population, the higher the rate of confirmed COVID-19 cases. The correlation (R²=0.29) is stronger than the correlation of any other variable examined, including both the median household income and the uninsured rate.

The rate of confirmed COVID-19 cases for communities where white people make up more than 70% of the population is four to five times higher than any grouping of cities where white people are less than half of the city.

Has the coronavirus epidemic accelerated through white, wealthy communities faster than in communities of color? It’s quite unlikely that there is some sort of epidemiological reason for this to be true. It is more likely that coronavirus testing is easier to access for white, wealthy communities, and that the true COVID-19 rate in poor communities and communities of color is being underreported.

I am not actually a train. Or a roadrunner. But I am originally from New Mexico.