New Covid-19 infections are no longer tracked or reported as accurately as during the public health emergency. Instead, U.S. officials are now focusing on testing the contents of Americans’ wastewater to control the virus.
To identify virus levels and broader trends, the U.S. Centers for Disease Control and Prevention relies on a large network of sampling sites at wastewater treatment facilities across the country. The monitoring network covers approximately 43% of the population.
The process does not accurately count the number of cases and readings can vary depending on wastewater flows at a particular location or the characteristics of a given variant at a given time. But it provides an early warning about viral spread, CDC officials say. CNN tracks these numbers each week nationwide and by state, and this page will automatically update as the agency releases new information.
Viral levels vary over time and by location. This table shows trends by state, with rankings in ascending order by severity of viral activity during the most recent testing period.
Samples are taken from sampling sites in the United States that meet the criteria to sufficiently anonymize the data. Sampling allows CDC to see results from a large snapshot of the population, not just the individuals who are in the health care system. Wastewater data also helps local public health agencies track new Covid variants and other infectious diseases, such as RSV and mpox.
The agency reports the percentage change in viral levels at each location where data was collected over a 15-day period, and some densely populated states have more testing locations than others. This map shows those locations. Some sites saw an increase in activity, while others saw a decrease.
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