Other things being equal, one would expect infection rates for airborne transmissible diseases such as COVID-19 to be directly proportional to population density. At the beginning of the pandemic here in the United States infection rates were highest in the large cities on the coasts. These are places with high population density as would be expected.
As time went on, we learned that masks and distancing can have a profound impact on decreasing infection rates. The locale of rapidly increasing infection rates has now shifted to the Midwest in states such as North and South Dakota.
Here are some interesting comparisons. Los Angeles County, population density of 2,100 per square mile, has a case rate of about 40 per 100,000. (average number of daily new cases over the last seven days.)
Guttenberg, New Jersey has the highest population density of any city in the United States. It is in Hudson County, across the Hudson River from Manhattan. The population density of Hudson County is 14,000 people per square mile and an infection rate of 50 per 100,000.
Now compare those rates in very densely populated areas where rates would be expected to be high with the rates in much less densely populated counties. Pope County, Arkansas has a population density of 74 per square mile and an infection rate of 55 per 100,000.
Buffalo County, South Dakota, population density of only 4 people per square mile, has an infection rate of 204 per 100,000. The population density of Hudson county is 3,500 times greater than Buffalo county, yet its infection rate is one quarter that of Buffalo County.
It should be glaringly obvious that something else is driving the infection rates beyond population density. That something is the willingness to address the steps necessary to disrupt the transmission of COVID-19. Some areas still have not mandated any wearing of masks, most notably South Dakota. It is no wonder that it has the highest ratio of case rates to population density in the United States.
Mandates to prevent the spread of COVID-19 come in multiple flavors, from lockdowns to unenforced mask mandates. Regardless of laws, the issue is compliance and rural areas seem to be the least compliant. It’s about freedom, right? But that freedom to ignore the pleadings of governors across the country really means the freedom to spread disease and death to loved ones and strangers alike.
Some claim a medical exemption to mask-wearing but there is zero evidence that a mask interferes with the passage of gasses such as Oxygen and Carbon Dioxide. Some with asthma claim an exemption even though most doctors will tell asthmatics that they are at a greater risk without a mask because of their condition. There have even been mask-burning events to protest this simple public health measure.
One wag put the problem this way: There are two issues, one is population density and the other is the density of the population. Listen to the experts, wash your hands frequently, properly wear a mask, and keep a distance. Not one or another, all of them.
Dr. Bob Allen is Emeritus Professor of Chemistry, Arkansas Tech University.