An archive of estimated trend categories, probabilities of epidemic growth, and Rt, updated weekly for COVID-19 and flu. Estimates are based on emergency department visits reported to the National Syndromic Surveillance Program (NSSP), and generated using a model that includes nowcasting to adjust for incomplete reports on the most recent dates. See the visuals supported by these data, and more information about the data, models and methods at https://www.cdc.gov/cfa-modeling-and-forecasting/rt-estimates/index.html, and https://www.cdc.gov/respiratory-viruses/data/activity-levels.html.

For a semi-technical overview of the modeling methods used to generate these estimates see https://www.cdc.gov/cfa-behind-the-model/php/data-research/rt-estimates/index.html.

For the code used to run the models, see https://github.com/CDCgov/cfa-epinow2-pipeline.

Tags: covid-19, coronavirus, cfa, influenza, flu, modeling, epidemic trend, rt, respiratory virus response, rvr

Last updated: 2026-01-23 17:01:29+00:00