Background

This report provides a brief summary of the weekly ensemble forecast from the COVID-19 Forecast Hub based on forecasts submitted on September 13, 2021. In collaboration with the US CDC, our team aggregates COVID-19 forecasts from dozens of teams around the globe. Typically on Wednesday of each week, a summary of the week’s forecasts from the COVID-19 Forecast Hub appear on the official CDC COVID-19 forecasting page.

Every week, teams submit their forecasts to the COVID-19 Forecast Hub. This past week, 48 models were submitted.

Each Monday evening or Tuesday morning, we combine the most recent forecasts from each team into a single “ensemble” forecast of reported COVID-19 cases at the county, state, and national level and deaths at the state and national level. At the moment, we only generate ensemble forecasts for four weeks into the future, as the available evidence suggests that models are less accurate at longer forecast horizons.

An archive of weekly reports from the COVID-19 Forecast Hub can be found at this page.

COVID-19 Forecasts

National level

This week, our ensemble combined forecasts from 38 different models.

At the national level, the ensemble model predicts that weekly totals of observed deaths in each of the next four weeks will be between 11,300 and 11,600 deaths with around 705,800 deaths by October 09 (95% prediction interval: 688,660 - 718,906).

For the week ending October 09, the ensemble forecasts that reported COVID-19 deaths in the US will be between 5,600 and 17,400 (95% prediction interval: 5,583 - 17,359).

For October 11, 2021 COVID-19 daily hospitalizations in the US will be between 5,000 and 15,300 (95% prediction interval: 5,032 - 15,306).

As of September 6, 2021 the ensemble forecast for cases only reports up to two-week ahead forecasts, due to persistent large inaccuracies observed when forecasting beyond two weeks. For the week ending September 25, the ensemble forecasts that reported COVID-19 cases in the US will be between 567,500 and 1,307,000 (95% prediction interval: 567,525 - 1,307,032).

You can explore the full set of models, including their forecasts for past weeks online at CDC’s interactive forecast visualization.

Deaths

Hospitalizations

Cases

State level

The ensemble model estimates that 46 states and territories of the US have a greater than 50% chance of having more deaths in the next two weeks compared to the past two weeks.The model forecasts that 17 states and territories have a greater than 75% chance of an increase over the next two weeks (Alaska, Delaware, Illinois, Indiana, Maine, Minnesota, Montana, North Dakota, Ohio, Pennsylvania, South Dakota, Tennessee, West Virginia, Wisconsin, American Samoa, Guam, Northern Mariana Islands).

The sortable and searchable table below shows the total number of reported COVID-19 deaths at the US level and by state over the last two weeks (ending Saturday, September 11, 2021) and the forecasted counts for the subsequent two weeks (ending September 25, 2021).

Looking at the rates allows for easier comparison across states, where you can see which states have had or are predicted to have proportionally higher rates in comparison to other states.

When interpreting probability of an increase, it’s important to note that the increase or decrease is relative to the location-specific recent observed incidence, which varies across locations.

Death rates

The sortable and searchable death table below shows the total number of reported COVID-19 deaths at the US level and by state as of Saturday, September 11, 2021 (“Total COVID-19 Deaths”) as well as the rate of reported COVID-19 deaths in the population (standardized per 100,000 population) over the last two weeks and over the next two weeks.

Hospitalization rates

The sortable and searchable hospitalization table below shows the 7 day average hospitalization count and rate of reported COVID-19 hospitalization in the population (standardized per 100,000 population) over the last week (September 05, 2021 to September 11, 2021) and two weeks ahead (September 19, 2021 to September 25, 2021).

Case rates

The sortable and searchable case table below shows the weekly case count and rate of reported COVID-19 case in the population (standardized per 100,000 population) over the last week (September 05, 2021 to September 11, 2021) and two weeks ahead (September 19, 2021 to September 25, 2021).

Methods & Acknowledgement

This report was reproducibly and dynamically generated using RMarkdown. The code for the report can be found here.