Respiratory Virus Activity Levels

Provides an update on how COVID-19, influenza, and RSV may be spreading nationally and in your state.

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Activity Levels Update:
  • The amount of respiratory illness causing people to go to the doctor for fever and cough or sore throat is low in most areas of the country. However, a few areas are reporting higher respiratory illness activity, which could have multiple causes.  CDC is actively following up with health departments in these communities.
  • Emergency department visits due to COVID-19 are higher than RSV and influenza but decreasing overall. Visits due to RSV remain low but are increasing. Visits for influenza are low.

Reported on Friday, October 20th, 2023.

Level of Respiratory Illness Activity

Activity levels determined weekly based on the percentage of visits to enrolled outpatient healthcare providers or emergency departments for fever and cough or sore throat reported to ILINet. Visits can be attributed to a variety of respiratory pathogens that cause these symptoms. Activity levels reflect how the percentage in the most recent week compares to what that jurisdiction typically experiences during low circulation periods. Trend information for the percentages used to calculate activity levels can be found at:  National, Regional, and State Level Outpatient Illness and Viral Surveillance (cdc.gov).


  • Source: U.S. Outpatient Influenza-Like Illness Surveillance Network (ILINet).
  • Additional information available at: Outpatient Illness Surveillance methods section.
  • This system monitors visits for respiratory illness that includes fever plus a cough or sore throat, (also referred to as influenza-like illness, or ILI), not laboratory confirmed infections; therefore, patient visits due to a variety of respiratory pathogens that cause similar symptoms may be captured.
  • The activity levels compare the mean reported percent of visits due to ILI during the current week to the mean reported percent of visits due to ILI during non-influenza weeks. The 13 activity levels correspond to the number of standard deviations below, at, or above the mean for the current week compared with the mean during non-influenza weeks.
  • This map uses the proportion of visits to enrolled outpatient healthcare providers or emergency departments for respiratory illness to measure the activity level within a state. It does not, however, measure the extent of geographic spread of respiratory illness within a state. Therefore, outbreaks occurring in a single city could cause the state to display high activity levels.
  • Data collected in ILINet may disproportionately represent certain populations within a state depending on enrolled providers, and therefore may not accurately depict the full picture of respiratory virus activity for the whole state.
  • The data presented in this map is preliminary and may change as more data is received.
  • Differences in the data presented by CDC and state health departments likely represent differing levels of data completeness with data presented by the state likely being the more complete.

Related Data Visualizations

Emergency Department Visits for Viral Respiratory Illness

Weekly percent of total emergency department visits associated with COVID-19, influenza, and RSV.


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Weekly Viral Respiratory Illness Snapshot

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Severe Viral Respiratory Illness