To this point, COVID-19 has had different effects in the two most populous cities in the United States:

Public health officials are keeping a wary eye and warning that LA could end up being as hard hit as New York in coming weeks, in part because a planned increase in testing may uncover a dramatic surge in cases. Testing in Los Angeles County is expected to increase from 500 per day to 5,000 by the end of the week…

In both cities, schools have been canceled, many businesses shuttered and employees who can have been ordered to work from home. New York City, with roughly 8.5 million residents, had nearly 45,000 cases and at least 366 deaths as of Friday, according to a tally by Johns Hopkins University. Los Angeles County, which contains its namesake city of 4 million people plus an additional 6 million residents, had nearly 1,500 cases and 26 deaths.

Health experts don’t know why there is such a big difference in the number of cases, but believe several things could be at play, such as urban density, differences in the use of mass transportation and slightly earlier moves by authorities to enact social distancing policies. A difference in the speed and amount of tests could also be factors, as officials warn that many people who get COVID-19 don’t necessarily have symptoms…

While a shortage of tests in California during the early weeks of the crisis is one reason for a much lower number of cases, it doesn’t alone explain the difference. New York has tested about three times as many patients, but it has 10 times as many cases as all of California.

There are a lot of possible moving parts (and combinations of these) that could explain the differences. I’m guessing there will be a lot of interesting research that comes out eventually that examines the interaction between place (and all the factors associated with that) and both the spread and consequences of COVID-19. The virus may spread to all areas eventually but the early stages suggest some differences across places.

Let’s say future research finds some differences between locations not just related to policies but to fundamental features of physical space such as density, mass transit use, and levels of social interaction. Will places be willing to change their behavior for the potential of a pandemic? In a world where locations brand themselves and look to attract residents and businesses (recent example), could traits that mean less exposure to infectious diseases represent a selling point?

One factor that I do not see mentioned in this article is the rate of travel in and out of each of these cities. Both are very important places located on coasts that experience a lot of travel in and out as well as much mobility across the region. But, does New York’s location in the the Northeast corridor matter and does New York City have significantly higher rates of global interaction and trade?