Emergency Department Visit Data for COVID-19, Influenza, and RSV

This page provides the percent of all emergency department (ED) visits with a diagnosis of COVID-19, influenza, or RSV (respiratory syncytial virus) by week.

The activity levels of COVID-19, influenza, and RSV in the ED are shown below and whether COVID-19, influenza, and RSV are increasing, decreasing, or stable in the previous week. In addition, ED visit data for these viruses are shown by age group.

ED visits and activity levels for COVID-19, influenza, and RSV

ED visits for COVID-19, influenza, and RSV for different age groups

ED visits by age groups for COVID-19, influenza, and RSV

Data shown are subject to change and will be updated as more information is available.

How to use the data visualizations

The three dashboards on this page are interactive and provide the percent of all emergency department (ED) visits with a diagnosis of COVID-19, influenza, or Respiratory Syncytial Virus (RSV) by week. Users can choose to view the data in these dashboards by using the hover options, changing the dates, or by clicking on dashboard buttons. Data are available since the week of September 7, 2019.

The first visual includes data for all age groups and includes activity levels and trajectory for each virus. The dashboard includes a dropdown menu allowing you to filter data to show data for one of the five Wisconsin public health regions.

The second visual allows the user to examine patterns of disease activity in a certain age group. For example, comparing the proportion of ED visits for COVID-19, RSV, and flu among those aged 0-4 years. The third visual allows the user to examine patterns of disease activity across age groups for the selected disease. For example, comparing the proportion of ED visits for COVID-19 among those aged 0-4 years with the proportion of ED visits for COVID-19 visits among those aged 65 years and older.

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.

The following ESSENCE diagnosis categories were used to define acute respiratory infection (ARI), COVID-19, influenza, and RSV:

Acute Respiratory Illness (ARI): CDC (Centers for Disease Control and Prevention) Broad Acute Respiratory DDv1
COVID-19: CDC COVID-Specific DDv1
Influenza: CDC Influenza DD v1
RSV: CDC Respiratory Syncytial Virus DDv1

Weekly percent of ED visits for ARI, COVID-19, influenza, and RSV are calculated by dividing the number of visits to the ED with a diagnosis meeting an above definition from Sunday through Saturday by the total number of visits to the ED for the same time period.

Additional resources

CDC Companion Guide: NSSP Emergency Department Data on Respiratory Illness.