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Wastewater Influenza A State and Territory Trends
Influenza A Wastewater Monitoring in the U.S.
- The ongoing avian influenza A (H5) (bird flu) outbreak in U.S dairy cows and poultry may be contributing to the moderate and high influenza (flu) A virus wastewater levels in some jurisdictions, based on reviewing multiple data sources. The risk to the public of avian influenza A (H5) is currently low.
- Wastewater data for influenza A virus should be considered in combination with clinical sources of influenza A data.
- Influenza A viruses include subtypes like avian influenza A(H5) virus and A(H1N1). Wastewater testing for overall influenza A virus cannot tell us what subtypes are present. Wastewater testing cannot tell us if the source of the influenza A virus is from humans, animals, or animal products.
- Wastewater testing for influenza virus subtypes, including an H5 subtype, is underway across the United States. See Wastewater Data for Avian Influenza A(H5) for more information.
- CDC and public health partners continue to investigate whether changing levels of influenza A virus in wastewater are related to seasonal influenza, the avian influenza A (H5) outbreak in animals, or both.
This page shows the current wastewater viral activity level of influenza A for the overall state or territory. If states do not have historical data available, the state/territory page is not available. This page also shows state/territory and national trends over time.
Wastewater data are updated every Friday with the previous week’s data, which allows for data to be reviewed for accuracy.
Current Site Levels – Download Data (CSV)
Trend Over Time – Download Data (CSV)
All State/Territory Wastewater Viral Activity Levels – Link to Dataset (JSON) | Download Data (CSV)
Wastewater monitoring can detect viruses spreading from one person to another within a community earlier than clinical testing and before people who are sick go to their doctor or hospital. It can also detect infections without symptoms. If you see increased wastewater viral activity levels, it might indicate that there is a higher risk of infection. See how to protect yourself from respiratory viruses.
About the Wastewater Viral Activity Level: The wastewater viral activity level indicates whether the amount of virus in the wastewater is very low, low, moderate, high, or very high. The wastewater viral activity levels may indicate the risk of infection in an area. The wastewater viral activity levels are categorized as follows:
- Up to 1.6 – Very Low
- Greater than 1.6 and up to 4.5 – Low
- Greater than 4.5 and up to 12.2 – Moderate
- Greater than 12.2 and up to 20.1 – High
- Greater than 20.1 – Very High
No Data: States or territories without sufficient data to estimate the wastewater viral activity level for the previous week are indicated as “No Data.” A label of “No Data” means that either:
- No data were reported this week from sites within the state or territory
- Data were reported this week, but sites within the state or territory do not have enough data (at least 10 weeks with consistent methodology) to estimate the Wastewater Viral Activity Level in the last week.
National and state data represent the median values across all wastewater treatment plants. To learn more on how the wastewater viral activity level is calculated, see Data Methods.
Data Limitations: Wastewater data cannot determine the source of influenza A viruses. Detections could come from a human or from an animal (like a bird) or an animal product (like milk from an infected cow).
