One of the most persistent myths about the threat of COVID-19 is that it is inextricably linked with population density. Since March, this explanation has shown up in magazine articles and news reports both domestically and internationally. It has appeared in the speeches of mayors and governors and the columns of pundits from across the ideological spectrum.
It has also been thoroughly debunked.
The supposed link between population density and COVID-19 doesn’t work at any scale. At the global level, coronavirus superstars include South Korea, Japan, Hong Kong and Singapore — all among the most densely populated countries on earth.
Countrywide statistics find no relationship between population density and COVID-19 death rates. To pick just one example, sparsely populated Canada has nearly 10 times more deaths per capita than tightly packed Bangladesh.
The explanation doesn’t work within U.S. borders either. While it’s true that America’s most densely populated city, New York, had one of the country’s worst outbreaks, its second densest city, San Francisco, had one of the least severe. On Jan. 6, North Dakota, which ranks 47th among the states in population per square mile, had twice as many COVID-19 cases per capita as New Jersey, which ranks first.
Density can’t even explain how the pandemic erupted within cities. In New York, the boroughs of Bronx and Queens have up to three times more deaths than Manhattan despite having half the population density. The same pattern has appeared everywhere from Chicago to Seattle to Nashville: Coronavirus outbreaks infect front-line workers, minorities, the poor and mask-deniers, regardless of how high their apartments are stacked on top of each other.
A Faulty Narrative
Beyond the numbers, the relationship between population density and COVID-19 spread doesn’t even make basic common sense.
Population density — the number of people per square mile — roughly measures how close people live to each other. It doesn’t measure the type of work they do, the frequency of their face-to-face interactions or how often they go to church. Since March, the coronavirus has struck dozens of rural areas via meatpacking facilities, prisons and superspreader events. Homes being spaced far apart does not prevent the activities that actually spread the virus.
So what does explain the vast differences between cities, states and countries in the severity of their COVID-19 outbreaks? The answer is primarily public health policy: Places with political leaders who instituted early lockdowns, strict mask orders and competent testing, tracing and quarantine regimes have passed through the pandemic relatively unscathed.
In America, the differences between states have little to do with intrinsic factors like population density, weather or demographics and more to do with the political ideology driving their leaders’ actions. The virus hit Northeastern states early and unexpectedly, causing a steep wave of cases and deaths. Since then, as the virus has settled into America’s existing divides, it has spread most rapidly in states where governors were reluctant to impose mandatory controls or reopened their economies before suppressing the virus. Of the 10 states with the highest current caseloads, seven have Republican governors.
Crowding, Not Density
This doesn’t mean there’s no relationship between population dynamics and the spread of the virus. The number of people living in each household may, in fact, be a significant driver of transmission. In October, a study in Tennessee and Wisconsin found that 53% of people who shared a home with a COVID-19 patient became infected within seven days.
Residential overcrowding is not the same as population density. A five-story apartment building with 10 studio apartments is densely populated, but presents little risk of coronavirus transmission because its residents are physically separated from each other. A suburban home with 10 people sharing bedrooms and living space, on the other hand, poses a significant risk.
This is one of the reasons that farmworkers have such high COVID-19 risk despite mostly working outside. Low pay forces them to live in shared indoor spaces rather than having their own apartments.
Overcrowding within residences may also explain why cities like Los Angeles, where most of the land is covered by single-family homes, are experiencing such severe outbreaks. Though it’s less than half as densely populated as New York City, LA has roughly double the rate of overcrowded housing.
Many smaller cities display the same dynamic. As long as it remains illegal to build multi-family apartment buildings and other density-friendly forms of housing, workers double up, growing families stay put and young people live with more roommates.
In other words, America’s problem may not be density, but the lack of it.