Influenza Hospital Admissions Forecast: The maroon line(circles) is(are) the original(current) confirmed admission data. The 1-4 week ahead forecast median is shown in grey. Blue shaded regions denote decadal, 95%, and 98% forecast intervals. See the 'About' tab for more information and the 'Interactive Maps' tab for a geographic heatmap representation of the forecasts.

Notes: The orange circles and right vertical axis illustrate the daily number of reporting hospital facilities. These reporting rates generally show both weekly and seasonal patterns. The 'current data' and 'model data' are plotted separately because the data is sometimes updated after the model is run—effecting forecast accuracy.


In the infectious disease group here at Predictive Science, we run simulations to predict influenza burden on a week-to-week basis in the United States. Here the overall burden of infuenza is measured using influenza hospital admissions. Thus our model seeks to forecast new hospital admissions for future weeks.


We use a Suseptible-Infectious-Recovered/Hospitalized (SIRH) model with a time-dependent basic reproduction number R0(t). The model is available as an open-source R package PROF. More information about the model and code examples are available at


Fitting the model to daily data is done via Markov Chain Monte Carlo (MCMC) process. This procedure maps the model-data likelihood distribution over parameter-space, revealing not only the best fit, but also the most likely model variations.


The posterior distribution of the fit is used to make state-specific probabilistic forecasts of the daily number of confirmed influenza hospital admissions. The national forecast is constructed using our 'error-correlation' procedure for combining the state level forecasts. States with low hospitalization rates are not fitted and are forecasted with a simple statistical model. We also use a statistical model when we believe that there is large uncertainty in future trends. The daily data and forecasts are aggregated to the weekly scale.

User Selections

Epidemic Week: Week of the year as defined by the Morbidity and Mortality Weekly Report (MMWR). In this setting 'epidemic week' selects the portion of the flu season to fit the model to.


Hospital Admission Data: The 'gold standard' for our forecasts is confirmed influenza admission data (field name: `previous_day_admission_influenza_confirmed`) from the COVID-19 Reported Patient Impact and Hospital Capacity by State Timeseries . This daily timeseries is provided by The U.S. Department of Health and Human Services. The data updates regularly and currently its reporting is mandatory. Here the daily forecasts and data are aggregated to the weekly scale.


Our influenza forecasting program is supported by the CDC and CSTE (under cooperative agreement number NU38OT000297)

For questions about this web site please contact:

Dr. M. Ben-Nun:

Dr. James Turtle:

Dr. Pete Riley:

Predictive Science Inc.
9990 Mesa Rim Rd, Suite 170
San Diego, CA 92121
Phone: (858) 450-6494