Wastewater monitoring can detect viruses spreading throughout the community earlier than clinical testing and before people who are sick go to their doctor or hospital. It can also detect infections without symptoms. 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.
About the Wastewater Viral Activity Level
The wastewater viral activity level (WVAL) 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 1.5 - Very Low
- Greater than 1.5 and up to 3 - Low
- Greater than 3 and up to 4.5 - Moderate
- Greater than 4.5 and up to 8 - High
- Greater than 8 - Very High
Calculating Wastewater Viral Activity Level
The Wastewater Viral Activity Level is a calculated measure that allows us to aggregate wastewater sample data to get state/territorial, regional, and national levels and see trends over time. For more information about how Wastewater Viral Activity Level is calculated, please see the CDC's website.
Data Sources
Citation: Centers for Disease Control and Prevention (CDC). National Wastewater Surveillance System (NWSS). https://www.cdc.gov/nwss/