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Laboratory-Based Respiratory Virus Data

These charts provide a weekly breakdown of the number and percent of laboratory tests that are positive for respiratory viruses, including influenza, RSV (respiratory syncytial virus), COVID-19, adenovirus, coronaviruses (seasonal, not including SARS-CoV-2/COVID-19), HMPV (human metapneumovirus), parainfluenza, and rhinovirus/enterovirus. Most clinical tests used cannot distinguish between rhinovirus and enterovirus.

The trajectory shows whether COVID-19, influenza, and RSV activity was increasing, stable, or decreasing.

 Additional respiratory illness data

Click the buttons below to see a current summary of respiratory virus activity or the percent of emergency department (ED) visits for a respiratory illness.

Laboratory-based data for COVID-19, influenza, RSV, and other viruses

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

How to use the data visualizations

The dashboards on this page are interactive and provide the percent of tests for respiratory viruses that are positive. Users can choose to view the data in these dashboards by using the hover options, changing the dates, or by clicking on dashboard buttons.

The first visual includes a bar graph displaying the number of tests, number of positive tests, and percent of tests positive for COVID-19, influenza, and RSV from the most recent week of data. A trajectory for each virus is also provided. The graph below the bar chart shows the percent of tests positive for these three viruses with data displayed from the past 13 months.

More detailed information and information on other viruses is displayed by clicking on the “see more details for these three viruses and data for additional viruses” button. The graph revealed displays percent positivity averaged over the previous three weeks of data and the interactive options allow users to examine a variety of viruses by clicking on the check boxes below the graph. The date range can also be changed on this graph.

To view information about the number of tests run for each of the viruses displayed, the user can click on the “View data by number of positive tests” button. Similar to the previous visual, this visualization allows the user to compare a variety of different viruses by clicking and unclicking the checkboxes and provides the option to change the date range. For this visualization and the previous visualization, data is available going back to the week of September 7, 2019. Users can return to the first visualization by clicking on the “Return to COVID-19, influenza, RSV view” button.

Technical data notes and data sources

Data source: National Respiratory and Enteric Virus Surveillance System (NREVSS).

NREVSS is a sentinel network of laboratories located through the U.S., including clinical, public health, and commercial laboratories. Participating U.S. laboratories voluntarily report the total number of weekly aggregate tests performed to detect select respiratory and enteric viruses, and the weekly aggregate positive tests to CDC NREVSS on a weekly basis. These diagnostic tests are limited to nucleic acid amplification tests (NAATs) or polymerase chain reaction (PCR) tests.

Calculation of percent positivity: The percent of tests positive is calculated by dividing the number of positive tests (for each virus) by the total number of tests administered (for that virus), then multiplying by 100% [(# of positive tests/total tests) x 100%]. The three-week moving average of percent positivity is used in these charts.​

Trajectory metric: The weekly trajectory is the measure of change in the percentage of positive tests for COVID-19, influenza, or RSV from the previous week to the following week. To be considered growing or shrinking, the percent change in the percentage of positive tests from the previous week to the current week must be at least 10%, or the percent change must be consistently higher or lower each week compared with the previous three weeks and the percent change from three weeks previous to the current week must be at least 10%.


Last revised April 12, 2024