Respiratory Virus Data: Emergency Department Data

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

How to use the data visualizations

The three sections of this dashboard 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 and dropdown menus. Data are available since the week of September 7, 2019.

The first visual, Statewide percent of emergency department (ED) visits with a diagnosis for COVID-19, influenza, RSV, or an acute respiratory illness (ARI), includes data for all age groups. The dashboard includes a dropdown menu allowing you to filter the data to show information for any of the five Wisconsin public health regions. This visual also shows the percent of ED visits with a diagnosis of acute respiratory illness, (ARI). ARI diagnoses represent a broad grouping of respiratory illnesses that lead to ED visits ranging from the common cold to COVID-19, influenza and RSV. Use the Select diagnosis buttons to add ARI to the visual.

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. This data is displayed side-by-side as both a percent of reported ED visits and the number of ED visits for each diagnosis. Use the Select an age group dropdown menu to change the age group.

The third visual allows the user to examine patterns of disease activity across age groups for the selected virus. 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. This data is displayed side-by-side as both a percent of reported ED visits and the number of ED visits for each age group. Use the Select a virus dropdown menu to change the virus.

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.