COVID-19 trends in urban vs rural Central Nebraska
Analysis of case counts
HASTINGS, Neb. (KSNB) - September 29,2020 saw the one millionth death during the COVID-19 pandemic which began earlier this year. Worldwide, there have been over 34 million cases, with the United States leading the count with nearly 7.5 million cases (12th in per capita cases). Nebraska just broke 45,000 cases on the 29th. Here, we’ll examine how urban trends can influence spread in adjacent rural counties.
Beginning with the Tri-Cities three-county area, Adams, Buffalo, and Hall, most of the cases early on were from the large outbreak in Hall County. Below are three graphs, one for each county, which show the daily new cases, and a line plotting the 14-day rolling total of new cases. This approximates recent, potentially active cases. The Left axis is for the daily cases, right for the 2-week sum. It is important to note that the scales change for each graph, to better visualize each county’s peaks and valleys through the 6-month period.
Clearly, Hall County has had a significant outbreak which is recently unmatched in their few cases. Between June 8 and September 29, Hall maintained a 14-day count under 100. Meanwhile, Buffalo County has surged well past the early peak from May, having now maintained over 100 cases in a 14-day period for two months straight. Adams has yet to match its peak from May, but is approaching. I have also included Dawson County; while Lexington is not in the “Tri-Cities,” it is a large county with well over 20,000 people.
Surrounding counties have seen variations on this early peak and recent rise as well, but as many counties have fewer than 10,000 people in them, the numbers can be a little noisy. Below, I have included data from selected counties (Clay, Hamilton, Howard, Kearney, Merrick, Phelps, Webster), which are major areas of proximity to these four counties. Together, they represent nearly 49,000 people, on par with the Tri-Cities counties.
Now, let us compare the two main groups, urban and rural, in one chart. Combining the Tri-Cities and Lexington into one “Urban Zone,” and the seven other counties mentioned earlier into the “Rural Zone," and see how they stack up in a raw number setting. Clearly, far more cases have occurred in the “Urban Zone,” with 165,970 people, and 4,790 cases of COVID-19. The “Rural Zone” has a total of 48,743 people, and recorded 665 cases in six months of the pandemic.
By percent, the Urban Zone has seen 2.89% of its population infected, whereas the Rural Zone has seen only 1.36%. One more view will show us a timeline of these cases, and finalize how they are related.
Here we see a striking similarity in local maxima and minima in the 2-week sum curves of the two zones. Note, this is adjusted for population; this takes into account how many people have been infected per 10,000 residents. Urban areas have far more interactions between people, so transmission of a disease can be higher and infect a greater proportion of people. Commuting, shopping, or visiting folks from the Rural Zone may encounter far more people in the Urban Zone. In the initial wave from March to June, the peak for both zones was within a week of each other, and both reached a minimum in mid June.
It is at this point that we see a very similar rise in cases, different from the initial outbreak. A contributing factor to this is likely the higher awareness of the disease, fewer businesses open, and lower human activity. Vigilant mask usage and social distancing became more familiar by June, rather than in Early April. The period between mid June and Late August is a testament to these mitigations and how they can slow spread of the disease.
Data for daily, county COVID-19 cases is from the New York Times GitHub, and can be found here.
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