Hopkins study finds population density not driving COVID-19 spread

Brightly painted rowhomes in the Charles Village area. (Live Baltimore)

Brightly painted rowhomes in the Charles Village area.   A new Johns Hopkins study concludes that population density alone is not a significant determinant of the spread of COVID-19. (Live Baltimore)

Urban density in and of itself doesn’t contribute to the spread COVID-19, according to a recent Johns Hopkins’ study, and the illness’s spread in Maryland mirrors those findings.

Assumptions that urban areas perpetuate the spread of the new coronavirus were contradicted in a study by Johns Hopkins Bloomberg School of Public Health published last week in the Journal of the American Planning Association. Baltimore, the state’s densest urban area, currently trails three suburban counties in number of infections and deaths supports the report’s conclusion.

“These findings suggest that urban planners should continue to practice and advocate for compact places rather than sprawling ones, due to the myriad well-established benefits of the former, including health benefits,” Shima Hamidi, the study’s lead author and Bloomberg assistant professor, said in a statement.

Recent polls show Americans rethinking their willingness to live in urban areas and dense suburban enclaves.Roughly 40% of adults overall — 43% of city dwellers and 23% of suburbanites — said they’d contemplate moving to more rural environs post-coronavirus outbreak, according to a Harris Poll released in May.

Those findings worry planners and environmentalists who have advocated for denser development patterns as a tool to promote health, and improve environmental conditions.

Those advocates tout dense development’s potential to improve residents’ health, largely by shortening commutes, and its ability to slow environmentally harmful development sprawl.

The study’s findings, however, indicate that density alone doesn’t lead to higher infection rates.

Johns Hopkins researchers examined 913 metro counties in the U.S. When factors like race and education were accounted for, the density of an area was not an indicator of increased infection rate.

Those researchers were also “surprised,” according to Johns Hopkins, to find urban density was not linked to higher death rates.

In fact, researchers discovered that doubling the activity density, after again controlling for factors such as race and education, reduced the death rate by 11.3%.

An area’s population size, the proportion of people at least 60 years old, rate of college education, and proportion of Black residents, all were better indicators of increased infections and death than urban density.

Maryland jurisdictions with the highest number of infections, as of Tuesday, were primarily suburban communities. Prince George’s, Montgomery and Baltimore counties all reported more infections than Baltimore city.

Prince George’s County has experienced the highest number of infections topping 18,000 confirmed cases since March. Montgomery County has suffered the second-highest number of cases with more than 14,200 infections. That’s followed by Baltimore County, where about half that number of residents have been infected, according to the Maryland Department of Health.

While Baltimore trails those jurisdictions in terms of population, it’s also generally more densely populated than its suburban counterparts, with its concentration of apartment towers and rowhomes.

The fact that density may not be a major culprit in spreading the disease comes as Maryland endured a surge in new COVID-19 cases and deaths Monday.

The disease’s resurgence follows Maryland’s move to ease restrictions on business operations and religious gatherings in recent weeks.

Smaller, less densely populated jurisdictions led the way in reopening earlier this month. Health experts place COVID-19’s incubation period at about 14 days.

Maryland recorded more than 400 new confirmed cases of the illness Monday, bringing the total number of certified infections in the state to more than 65,000 since early March.

Another 18 people died of the disease on Monday, according to the health department, which raised the number of residents killed by the illness since early March to nearly 3,000.


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