Respiratory Illness Data Snapshot
This page is a summary snapshot of the latest information on viral respiratory illness in Wisconsin. It shows the respiratory illness activity level and trajectory for the previous week and provides key findings regarding respiratory virus transmission in Wisconsin. Additional respiratory data dashboards and webpages are linked below.
What to know
- Statewide respiratory illness levels are high.
- COVID-19 levels are moderate and increasing based on emergency department, laboratory testing, and wastewater data.
- Influenza and RSV are circulating at low levels and activity continues to increase.
- Now is the time to get the influenza, COVID-19, and RSV vaccines.
- To read about our recent confirmed human case of Highly Pathogenic Avian Influenza A(H5N1), visit our outbreak investigations webpage.
- DHS issued a health alert in October regarding an increase in Mycoplasma pneumoniae infections.
- For information about the pertussis outbreak, visit our outbreak investigations webpage.
What you can do
Even when respiratory illness levels are low, it is important to keep up with prevention strategies. Follow these tips to help keep you and your loved ones healthy:
- Stay up-to-date with vaccines.
- Take steps for cleaner air, such as gathering outside or bringing in outside air.
- Wash your hands and practice good hygiene.
- Cover coughs and sneezes.
- Stay home if you are sick.
Additional precautions, such as wearing a mask and physical distancing, should be considered when illness levels are moderate or high or if you or people around you have risk factors for severe illness.
Where to find more data dashboards
- Emergency department (ED) data: Find data on all ED visits with a diagnosis of COVID-19, influenza, or respiratory syncytial virus (RSV) by week.
- Laboratory data: Find data about laboratory tests positive for adenovirus, COVID-19, HMPV, and additional respiratory viruses.
- Death data: Find data about deaths related to respiratory illnesses.
Data shown are subject to change. Past data will be updated as more information is available.
How to use the data visualizations
The dashboard on this page provides the respiratory illness levels and trajectories for emergency department visits associated with overall respiratory illness, COVID-19, influenza, and RSV for the most recent week of data.
The line graph shows the percent of all emergency department (ED) visits with a diagnosis of a respiratory illness by week. Users can hover over the trend line on the graph to see more detailed information.
The dashboard includes a dropdown menu allowing you to filter data to show data for one of the five Wisconsin public health regions.
Technical data notes and data sources
Data source: ESSENCE (Electronic Surveillance System for Early Notification of Community Based Epidemics) from the National Syndromic Surveillance Program.
Approximately 95% of non-federal Wisconsin emergency departments (EDs) are represented in the dataset, and most EDs transmit visit information into ESSENCE within 24 hours.
Overall respiratory illness activity trends over time are calculated using ED visits meeting the CDC (Centers for Disease Control and Prevention) Broad Acute Respiratory Discharge Diagnoses (DD v1) ESSENCE category, which measures acute respiratory infection (ARI). This measure uses diagnoses for viral illnesses such as COVID-19, influenza, and RSV, in addition to general respiratory illnesses, such as cough or sore throat to measure the overall respiratory illness in the community.
Weekly proportion of ED visits for respiratory illness is calculated by dividing the number of visits to the ED with a diagnosis meeting the CDC Broad Acute Respiratory DDv1 definition from Sunday through Saturday by the total number of visits to the ED for the same time period.
Level metric: Activity level metrics for overall respiratory illness, COVID-19, influenza, or RSV categorize the current amount of visits to the ED for each of these conditions compared to the amount of visits during times of the year when these viruses are circulating at their lowest level in the community. Activity levels for the 2024-2025 respiratory season are calculated using ED visits meeting the following ESSENCE diagnosis categories:
- Overall respiratory illness: CDC Broad Acute Respiratory DDv1
- COVID-19: CDC COVID-Specific DDv1
- Influenza: CDC Influenza DD v1
- RSV: CDC Respiratory Syncytial Virus DDv1
Activity levels are provided by CDC. To view the detailed methodology used to calculate these values, see the CDC data notes describing these calculations.
| Level | Percent of weekly ED visits for overall respiratory illness | Percent of weekly ED visits for COVID-19 | Percent of weekly ED visits for influenza | Percent of weekly ED visits for RSV |
|---|---|---|---|---|
| Minimal | 0% to <10.6% | 0% to <0.5% | 0% to <0.1% | 0% to <0.05% |
| Low | 10.6% to <14.4% | 0.5% to <1.4% | 0.1% to <1.8% | 0.05% to <0.4% |
| Moderate | 14.4% to <18.2% | 1.4% to <2.3% | 1.8% to <3.4% | 0.4% to <0.8% |
| High | 18.2% to <22.0% | 2.3% to <3.3% | 3.4% to <5.0% | 0.8% to <1.2% |
| Very High | 22.0% or above | 3.3% or above | 5.0% or above | 1.2% or above |
Trajectory metric: The weekly respiratory illness trajectory for each diagnosis is the measure of change in the proportion of ED visits from the previous week to the next week.
- There are two ways for the trajectory to be increasing or decreasing.
The percent change of the proportion of ED visits from the previous week to the current week must be at least 5% for overall respiratory illness or 10% for COVID-19, influenza, and RSV. - The percent change must be consistently higher or lower for three consecutive weeks, and the percent change from the first week to third week must be at least 5% for overall respiratory illness or 10% for COVID-19, influenza, or RSV.
Additional resources
CDC Companion Guide: NSSP Emergency Department Data on Respiratory Illness.
Learn more about the CDC calculated levels.