Early Research on the COVID-19 Pandemic and Density

Almost as soon as the COVID-19 pandemic hit in early 2020, news outlets began positing the question of whether people were more likely to contract the virus in dense urban areas where they more often came into contact with people.

Especially in the pandemic's early period, as New York City's infection and mortality rates dominated the news cycle, this link between density and the spread of the virus felt natural and likely affected the decision of many urban residents to move deeper into suburban and rural areas.

Density and COVID-19: Early Findings

Shima Hamidi, Sadegh Sabouri, and Reid Ewing are some of the first to formally study the link between density and pandemics concerning COVID-19 in their recent article "Does Density Aggravate the COVID-19 Pandemic? Early Findings and Lessons for Planners" in the Journal of the American Planning Association (Vol. 86, No. 4).

The authors employ structural equation modeling to test the effects of several demographic and pandemic-related variables on COVID-19 infection and/or death rates (each logged for the model) at the county level. These include the percentage of Black population, COVID-19 testing rate, and metropolitan population.

A full list of regression variables can be found in this figure:

Figure 1: Causal path diagram for COVID-19 death rate in terms of county density and other variables (correlational arrows among explanatory variables are not shown for the sake of simplicity and clarity).

Connectivity Over Density in Pandemic

From this model, they find that the metropolitan population is one of the most significant predictors of COVID-19 infection and mortality rates.

Population density was not significantly related to the infection rate, and more dense counties had significantly lower COVID-19 mortality rates than those with low densities.

The authors posit that this may be because higher-density counties have superior healthcare systems that reduce the likelihood of COVID-19 mortality. Ultimately they use these findings to suggest that connectivity between counties (signified by larger metropolitan populations) matters more than density in the spread of the pandemic.

Based on this finding, the authors recommend that planners continue to advocate for dense development, adding lower COVID-19 death rates to a long list of benefits denser development can bring. In doing so, they are acknowledging that this pandemic has the potential to greatly shift urban planning practices for better or worse, but that it is, therefore, the responsibility of pro-density planners to counter pandemic-fueled arguments in favor of sprawl.

While this article represents only early findings that have potentially shifted in the seven months since the article was written, this link between urban form and the spread of COVID-19 is sure to be a major research topic in the coming years.

Top photo: Getty Images photo.