Models show how COVID-19 cuts a neighborhood path

October 29, 2020

The coronavirus doesn't spread uniformly through a community.

But in the world of disease modeling, many projections take a high-level approach to a geographic area, like a county or state, and forecast based on a general idea that a virus will take root and spread at an equal rate until it reaches its peak of infection.

A research team led by UC Irvine and the University of Washington has created a new model of coronavirus diffusion through a community. This approach, Proceedings of the National Academy of Sciences, factors in network exposure -- whom one interacts with -- and demographics to simulate at a more detailed level both where and how quickly the coronavirus could spread through Seattle and 18 other major cities.

The team used U.S. Census Bureau tract demographics, simulation techniques and COVID-19 case data from spring 2020 to estimate a range of days for the virus to spread within a given city.

The result: Some neighborhoods peak sooner than others. And in every city, the virus sticks around far longer than some might expect.

"The most basic takeaway from this research is risk. People are at risk longer than they think, the virus will last longer than expected, and the point at which you think you don't need to be vigilant means that it just hasn't happened to you yet," said co-author

Almquist and the team took on their study with two basic premises: Account for the social and geographic connections within a tract that could affect the course of the virus; and assume no vaccine or other major intervention alters its path. Then, based on actual COVID-19 and demographic data, project a likely scenario for spread over time.

Take Seattle. The study's map of the city outlines each census tract and provides a color-coded range of days each tract could take to reach peak infection before the virus goes into a low remission. The overall range is vast, from neighborhoods with the fastest peak -- 83 days -- to those that take more than 1,000. That's more than three years, assuming there is no significant intervention to stem the spread.

Denser neighborhoods in Seattle, such as Capitol Hill or the University District, reach peak infection rate earlier. But simulations predict that even nearby neighborhoods won't reach peak infection until weeks or even years later. These models predict more "burst-like" behavior of the virus' spread than standard models -- with short, sudden episodes of infection across the city, Almquist said.

In the study's model of Washington, D.C., census tracts also appear to reach peak infection rates at different times. Again, denser areas tend to peak sooner. But the network connections can cause "bursty" peak infection days, with some areas seeing early peak infections and others seeing it much later based on the neighborhoods' relative connections with each other, Almquist said.

Projecting the path of the virus can help estimate the impact on local hospitals. Researchers predicted this in several ways, such as modeling the number of cases per hospital over time and the number of days a hospital is at peak capacity.

The model of projected hospital cases shows how the geographic variations in the timing in peak COVID-19 infections could affect hospitals in different areas. Without outside intervention, some hospitals would remain at capacity for years, especially those farthest from major population centers.

These types of models are important because they provide a more detailed and nuanced prediction of an unknown like the novel coronavirus, said Almquist. Gauging how the virus might spread throughout a city and strain its hospitals can help local officials and health care providers plan for many scenarios. And while this study assumes no major interventions will rein in the virus, it's reasonable to believe the virus will linger to some degree, even with solutions such as a vaccine, according to Almquist.

"If you project these models for what it means over the country, we might expect to see some areas, such as rural populations, not see infection for months or even years before their peak infection occurs," Almquist said. "These projections, as well as others, are beginning to suggest that it could take years for the spread of COVID-19 to reach saturation in the population, and even if it does so it is likely to become endemic without a vaccine."
Co-authors are Loring Thomas, Peng Huang, Fan Yin, Xiaoshuang Iris Luo, John Hipp and Carter Butts, all of UC Irvine. The study was funded by the National Science Foundation and UC Irvine.

For more information, contact Almquist at

University of Washington

Related Virus Articles from Brightsurf:

Researchers develop virus live stream to study virus infection
Researchers from the Hubrecht Institute and Utrecht University developed an advanced technique that makes it possible to monitor a virus infection live.

Will the COVID-19 virus become endemic?
A new article in the journal Science by Columbia Mailman School researchers Jeffrey Shaman and Marta Galanti explores the potential for the COVID-19 virus to become endemic, a regular feature producing recurring outbreaks in humans.

Smart virus
HSE University researchers have found microRNA molecules that are potentially capable of repressing the replication of human coronaviruses, including SARS-CoV-2.

COVID-19 - The virus and the vasculature
In severe cases of COVID-19, the infection can lead to obstruction of the blood vessels in the lung, heart and kidneys.

Lab-made virus mimics COVID-19 virus
Researchers at Washington University School of Medicine in St. Louis have created a virus in the lab that infects cells and interacts with antibodies just like the COVID-19 virus, but lacks the ability to cause severe disease.

Virus prevalence associated with habitat
Levels of virus infection in lobsters seem to be related to habitat and other species, new studies of Caribbean marine protected areas have shown.

Herpes virus decoded
The genome of the herpes simplex virus 1 was decoded using new methods.

A new biosensor for the COVID-19 virus
A team of researchers from Empa, ETH Zurich and Zurich University Hospital has succeeded in developing a novel sensor for detecting the new coronavirus.

How at risk are you of getting a virus on an airplane?
New 'CALM' model on passenger movement developed using Frontera supercomputer.

Virus multiplication in 3D
Vaccinia viruses serve as a vaccine against human smallpox and as the basis of new cancer therapies.

Read More: Virus News and Virus Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to