Minnesota has now tested 4000+ people for Coronavirus with 137 positive results, so the samples are getting big enough to draw some inferences from. Mayo Clinic home Olmstead County is a hot spot, with 12 cases in a population of 157 thousand, roughly 1 for every 13,000. Hennepin County is pretty hot with 52 cases in a population of one and a quarter million, about one for every 24 thousand. Adjoining Ramsey county has 17 cases in a population of about 550 thousand, But a cluster of 5 cases in Martin county down at the bottom of the map with a population of only around 20 thousand gives them the most cases per capita.
So what’s up with all these counties in the north (top) of Minnesota with no cases? Just the counties north of the bottom of Cass and St.Louis counties have a combined population of nearly 400 thousand, and if they had the same ratio of cases to population as the rest of the state they’d have 10 cases, but this rural area has none. Unlike most of the counties with cases, they have no air passenger service of any volume and no interstate highways. Hennepin County’s freeway traffic counts are near 200,000 vehicles a day in spots, and even Olmstead’s push 100,000. The counties with no cases in north central Minnesota have few highways with over 10,000.
Air passenger volumes pretty well predicted the spread of Coronavirus from China, and it appears that highway traffic volumes may predict Coronavirus community spread beyond metropolitan areas. Thus it appears that rural isolation can slow if not stop the spread of the Coronavirus, suggesting that we can slow the spread of the virus by reducing the need for people in both rural and urban areas to travel.
Glad I live in a town of 39 on two lane highways...