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Forecasting COVID-19 Transmission Across Time in U.S. Counties

Statement of Problem

As the nation responded to the generational challenge of the COVID-19 pandemic, forecasting viral transmission across local communities became an important tool for planning and response. In the initial phase of the pandemic, this information was critical to help local, state and federal leadership make informed decisions about public policy solutions to manage the crisis.

Following the first wave of the pandemic in March 2020, there was a need to expand on robust and reliable data models that were increasingly relevant to local communities to inform their safe reopening. Together with reviewing emerging data on school and community safety, these data also helped communities navigate decision-making regarding returning more children to in-school instruction.  

With available vaccines and regional variability in community transmission rates, COVID-19 is now transitioning toward an endemic virus with seasonal peaks in transmission; even so, we would anticipate additional periods of resurgence ahead, and it will be crucial to provide scientific evidence to support speedy and accurate responses.


COVID-Lab: Forecasting COVID-19 Transmission Across Time in U.S. Counties


Through their COVID-Lab model, our interdisciplinary team across Children’s Hospital of Philadelphia and the University of Pennsylvania offered county-level data on test positivity and case counts from April 2020 to April 2022.

Next Steps

As mentioned above, we will continue to monitor community transmission and may provide updates from time to time through PolicyLab’s social media channels and blog to help guide the public should conditions change. The team is also working on additional peer-reviewed articles based on this project and continues to mentor early career scientists in utilizing their modeling methods.

For more on PolicyLab's COVID-19 response and guidance to assist schools and communities with reopening strategies, click here.

This project page was last updated in October 2022.

Suggested Citation

Children's Hospital of Philadelphia, PolicyLab. Forecasting COVID-19 Transmission Across Time in U.S. Counties. [Online]. Available at: [Accessed: plug in date accessed here].