Forecasting the Impacts of Weather and Social Distancing on COVID-19 Transmission Across the U.S.

Statement of Problem

As the nation mobilizes to respond to the once-in-a-century challenge of the COVID-19 pandemic, there is an urgent need to project how the virus will spread in the coming months. This information is critical to help local, state, and federal leadership make informed decisions about public policy solutions to manage the crisis.

To respond to the pandemic, society largely shut down through a variety of social distancing interventions that varied in magnitude and timing, and were designed to help slow the rate of infection, or flatten the curve. Flattening the curve was essential to prevent overwhelming health care systems, particularly with increased demands for ICU beds and ventilators, as well as to improve access to rapid and serologic testing for public health surveillance.

As the pandemic spreads in varied ways among our cities, it will be critical to provide more robust and reliable data models to guide decision-making about when and how to relax social distancing interventions in a way that allows Americans to safely transition back to work and school.

Description

Forecasting the Impacts of Weather and Social Distancing on COVID-19 Transmission Across the U.S.

Our interdisciplinary team across Children’s Hospital of Philadelphia and the University of Pennsylvania is using local data to provide short-term forecasts based on current social distancing practices.

Our interdisciplinary team across Children’s Hospital of Philadelphia and the University of Pennsylvania is using actual case data to longitudinally project, in real-time, the epidemic across 389 counties with active outbreaks as it spreads across the United States.

Other COVID-19 models project the disease’s impact across states/large areas, but our model focuses more locally by forecasting the spread of COVID-19 within counties, still capturing 68% of the U.S. population and 47 states plus Washington D.C. Through this model, we are accounting for the impact of weather, health and demographics of the population and city characteristics in order to: define the influence of temperature and humidity on SARS-CoV-2 transmission; determine the impact of social distancing in modifying the trajectory of SARS-CoV-2 transmission during current and future outbreaks; investigate how city characteristics modify the transmission; and forecast the effects of policy change and social distancing practices on the risk for virus resurgence.

Previously, the team provided 120-day COVID-19 case projections for 211 counties with active outbreaks since early March. The model now includes 389 counties with active outbreaks, which are a subset of nearly 600 counties the team is modeling that are home to more than 100,000 people. Additionally, the research team pivoted their strategy to shortened forecasts over a four-week horizon. Overall, the data indicates that the risk for large second waves of outbreaks remains low if communities continue to implement cautious, incremental plans to reopening that maintain limited travel to select non-essential businesses.

The latest updates to the model released on May 27 shows some communities, particularly in the southern and Midwestern regions of the country, are still at high risk for COVID-19 resurgence in the coming weeks, while many other counties appear to be flattening the curve, even if case counts are higher than two weeks ago. To view a data visualization of our findings, click here, and to learn more about the methods of this model, see this abstract.

Next Steps

Using this real-time data, we are engaging with local, state, and federal policymakers who are managing the COVID-19 response to support their efforts. We aim to inform a safe approach to reopening society that also accounts for the economic and social impacts shelter-in-place strategies are having on low-income families and communities.

For more on PolicyLab's COVID-19 response, click here and here

This project page was last updated in May 2020.

Suggested Citation

Children's Hospital of Philadelphia, PolicyLab. Forecasting the Impacts of Weather and Social Distancing on COVID-19 Transmission Across the U.S. [Online]. Available at: http://www.policylab.chop.edu. [Accessed: plug in date accessed here].