A notable feature of the coronavirus pandemic has been the speed with which it has spread the world. Of course, as new research from the University of Chicago reminds us, the spread has not been equally fast throughout each country, with cities spreading the virus roughly 2.5 times as fast as smaller towns.
The researchers explain, however, that whilst cities tend to have a faster spread of the virus, they also have the institutions and infrastructure to respond more aggressively too, whether in terms of expanding the capacity of their healthcare systems or enforcing social distancing measures.
“You can see large cities being hit first and faster, and then stepping up their responses,” they say. “If their response matches the challenge, then they have a chance to go through this first surge faster, and also to be better prepared for the future.”
Tracking the spread
The researchers examined data from over 200 American cities and metropolitan areas from March 13th to the 24th. They aggregated county-level data to the city level, before subtracting all deaths in order to approximate the number of active cases each area had. This allowed them to estimate the growth rate of the virus, with some of the highest found in the New York-Newark-New Jersey area, which experienced 50% growth per day, and Chicago, which experienced 43% growth per day.
“The denser the city, the more easily disease can spread,” the researchers say. “It’s intuitive, but we put numbers behind it. This evidence is important from a public policy standpoint, because you have some politicians really not taking some of these things sufficiently seriously.”
The researchers believe their findings underline the particular importance of being careful if you live in a large city, and that officials need to respond faster in such places.
Return to normal
The research also suggests that because the spread of the virus in smaller towns and cities is less virulent, they might also be able to return to normal faster than their larger counterparts. although the researchers do caveat that by highlighting the clear potential for transmission between cities.
What they hope their work does remind us, however, is that the path to normality will be place-specific, and the density of ties that can help to spread the disease will play a major part.
The researchers are currently examining the data to see if it can also reveal the effectiveness of countermeasures, especially on a local level, to see if different places warrant different responses.
“It’s not a monolithic problem,” they conclude. “The attack rate is worse in some areas, but the capacity to respond may also be stronger in different places. Where these two factors match, or don’t match, is where we’ll find both solutions and the greatest challenges.”
