COVID-19 Forecasts: Cases
Reported and forecasted new COVID-19 cases as of September 13, 2021.
Interpretation of Forecasts of New Cases
- Ensemble forecasts combine diverse independent team forecasts into one forecast and have been among the most reliable in performance over time. However, even the ensemble forecasts have failed to reliably predict rapid changes in the trends of reported cases, hospitalizations, and deaths. Due to this limitation, they should not be relied upon for decisions about the possibility or timing of changes in trends.
- This week’s national ensemble predicts 290,000 to 1,360,000 new cases are likely to be reported in the week ending October 9, 2021.
- Case forecasts were not assessed for likely increases or decreases because more reported cases than expected have fallen outside the forecast prediction intervals.
- The figure shows the number of new COVID-19 cases reported in the United States each week from July 10 through September 11 and forecasted new cases over the next 4 weeks, through October 9.
- This week, ensemble forecasts of new reported COVID-19 cases included forecasts from 24 modeling groups, each of which contributed a forecast for at least one jurisdiction.
- Models make various assumptions about the levels of social distancing and other interventions, which may not reflect recent changes in behavior. See model descriptions below for details on the assumptions and methods used to produce the forecasts.
State & County Forecasts
State-level and county-level forecasts show the predicted number of new COVID-19 cases for the next 4 weeks by jurisdiction. Each forecast figure uses a different scale due to differences in the number of COVID-19 cases between jurisdictions. To aid in comparisons between jurisdictions, the ensemble plot for each location has a second axis (in grey) that shows the expected number of cases per 100,000 people. Only forecasts meeting a set of ensemble inclusion criteria are shown; further details are available here: https://covid19forecasthub.org/doc/ensemble/external icon. Plots of the state-level and county-level ensemble forecasts and the underlying data can be downloaded below.
Additional forecast data and information on forecast submission are available at the COVID-19 Forecast Hubexternal icon.
Forecast Inclusion, Evaluation, and Assumptions
The teams with forecasts included in the ensembles are displayed below. Forecasts are included when they meet a set of submission and data quality requirements, further described here: https://github.com/reichlab/covid19-forecast-hub#ensemble-modelexternal icon.
Ensemble and individual team forecast performance is evaluated using a variety of metrics, including the assessment of prediction interval coverage, available at https://delphi.cmu.edu/forecast-eval/external icon.
The forecasts make different assumptions about social distancing measures. Additional individual model details are available here: https://github.com/cdcepi/COVID-19-Forecasts/blob/master/COVID-19_Forecast_Model_Descriptions.mdexternal icon
Intervention assumptions fall into multiple categories:
- These modeling groups make assumptions about how levels of social distancing will change in the future:
- Columbia Universityexternal icon (Model: Columbia)
- Massachusetts Institute of Technology, Operations Research Centerexternal icon (Model: MIT-ORC)
- These modeling groups assume that existing social distancing measures in each jurisdiction will continue through the projected 4-week time period:
- Bob Paganoexternal icon (Model: BPagano)
- University of Colorado, Boulderexternal icon (Model: CUBoulder)
- Federal Reserve Bank of San Francisco/Wilsonexternal icon (Model: FRBSF-Wilson)
- IEMexternal icon (Model: IEM)
- Johns Hopkins University, Applied Physics Labexternal icon (Model: JHU-APL)
- Johns Hopkins University, Center for Systems Science and Engineeringexternal icon (Model: JHU-CSSE)
- Johns Hopkins University, Infectious Disease Dynamics Labexternal icon (Model: JHU-IDD)
- Karlen Working Groupexternal icon (Model: Karlen)
- Los Alamos National Laboratoryexternal icon (Model: LANL)
- Masaryk Universityexternal icon (Model: Masaryk)
- MIT-Cassandraexternal icon (Model: MIT-Cassandra)
- Massachusetts Institute of Technology, Institute for Data, Systems, and Societyexternal icon (Model: MIT-ISOLAT)
- Microsoft AIexternal icon (Model: Microsoft)
- Northeastern University, Laboratory for the Modeling of Biological and Socio-technical Systemsexternal icon (Model: MOBS)
- Pandemic Centralexternal icon (Model: PandemicCentral)
- Qi-Jun Hongexternal icon (Model: QJHong)
- Robert Walravenexternal icon (Model: ESG)
- University of Central Floridaexternal icon (Model: UCF)
- University of Georgia, Center for the Ecology of Infectious Diseaseexternal icon (Model: UGA-CEID)
- University of Michiganexternal icon (Model: UM)
- University of Southern Californiaexternal icon (Model: USC)
- This modeling group makes both assumptions, combining different models:
- The University of Virginiaexternal icon (Model: UVA)
1The full range of the prediction intervals is not visible for all state plots. Please see the forecast data for the full range of state-specific prediction intervals.